The Monterey County Democratic Central Committee and two of its members (the Committee) challenge a district court order denying the Committee’s request for an injunction of a United States Postal Service guideline prohibiting voter registration by partisan groups on postal premises. We affirm.

FACTUAL AND PROCEDURAL BACKGROUND

In December 1983 the United States Postal Service (Postal Service) promulgated a guideline permitting voter registration on postal premises under certain conditions and only by certain groups. Postal Bulletin 21434, 12-1-83 at 9, reproduced in Appendix A, infra. Section (A)(1) of the guideline defines permissible registrars as “government agencies or non-profit civic leagues of organizations that operate for the promotion of social welfare but do not participate or intervene in any political campaign on behalf of any candidate for any public office.”

In July 1984 the Committee sought permission to register voters at the Post Office in Carmel Valley, California (Post Office). The Committee proposed to seat its members at tables located on a covered walkway adjacent to the Post Office. The walkway is separated from municipal sidewalks by the Post Office parking area. Photographs reproduced in Appendix B, infra. Terry Williams, Postmaster of the Carmel office, denied the Committee’s request, finding that the Committee was a partisan group not authorized to conduct voter registration under section (A)(1).

*1196 The district court preliminarily enjoined enforcement of the guideline but later granted summary judgment in favor of the Postal Service. We review an order of summary judgment de novo. Ashton v. Cory, 780 F.2d 816, 818 (9th Cir.1986). DISCUSSION

The Committee contends that by excluding partisan groups from voter registration activities on Post Office property, the guideline deprives them of their first amendment right of free expression and fifth amendment equal protection guarantees.

A. The Public Forum Doctrine and the First Amendment

The parties do not dispute that voter registration is speech protected by the first amendment to the United States Constitution. This protection, however, is not in all cases absolute. See Heffron v. Int’l Society for Krishna Consciousness, Inc., 452 U.S. 640, 647 , 101 S.Ct. 2559, 2564 , 69 L.Ed.2d 298 (1981) (“the First Amendment does not guarantee the right to communicate one’s views at all times and places or in any manner that may be desired”). See also Adderley v. Florida, 385 U.S. 39, 47-48 , 87 S.Ct. 242, 247-48 , 17 L.Ed.2d 149 (1966). The values embodied in the first amendment are expressed through rules that balance tenets of free expression— principles constituting the hallmark of free societies — with practical assessments of the suitability of the forum. The nature of the forum selected by the speaker determines which rule governs.

Fora are grouped into three categories. The first includes places which “by long tradition or government fiat” have been utilized for assembly and debate. Perry Education Assoc, v. Perry Local Educators’ Assoc., 460 U.S. 37, 45 , 103 S.Ct. 948, 954 , 74 L.Ed.2d 794 (1983). Public fora typically include streets, sidewalks and parks. Id. Government authority to regulate speech in these “quintessential” public fora is greatly limited. Id. In such places, communication may not be entirely prohibited. Content-based exclusions are impermissible unless justified by a compelling state interest narrowly tailored to achieve that end. Id. The government may enforce content-neutral regulations concerning time, place and manner of expression which are narrowly drawn to serve “a significant government interest, and leave open ample alternative channels of communication.” Id.

A second category of forum includes public property opened and designated by the state for the public as a place of expressive activity. Id. The government does not create a public forum through unconscious, unspoken practices or by permitting limited discourse, but “only by intentionally opening a non-traditional forum for public discourse.” Cornelius v. NAACP Legal Defense and Education Fund, Inc., 473 U.S. 788 , 105 S.Ct. 3439, 3449 , 87 L.Ed.2d 567 (1985). Courts refer to such fora as “limited” public fora, Perry, 460 U.S. at 48 , 103 S.Ct. at 956 , or public fora “by designation.” Cornelius, 105 S.Ct. at 3450 . First amendment questions involving these places are controlled by the rules applicable to traditional public fora.

Public fora by designation often will be narrowly defined. Thus, when limited discourse is permitted by select groups, a public forum open to indiscriminate use by all is not created. Cornelius, 105 S.Ct. at 3449 . In such instances a limited public forum results, extended only to the original recipients of the government’s permission and to entities similar in character. Perry, 460 U.S. at 47-48 , 103 S.Ct. at 956-57 . Once opened, a limited public forum is not guaranteed an indefinite existence; the government may choose to close it and devote the property exclusively to its preexisting purposes. 460 U.S. at 46 , 103 S.Ct. at 955 .

The third category consists of nonpublic fora. In describing the government's powers to regulate these places, the Supreme Court has stated: “the State may reserve the forum for its intended purposes, communicative or otherwise, as long as the regulation on speech is reasonable and not an effort to suppress expression merely *1197 because public officials oppose the speaker’s view.” Id.

It is the Committee’s position that the walkway is a traditional public forum. The guideline, they argue, furthers no compelling government interest and thus cannot withstand the heightened scrutiny applied to regulations of public fora. We disagree.

Public places of outdoor pedestrian traffic — sidewalks—long have been representative of areas held open to the public for expressive activities. United States v. Grace, 461 U.S. 171, 179 , 103 S.Ct. 1702, 1708 , 75 L.Ed.2d 736 (1983). That a sidewalk is situated on publicly owned property without more, however, is insufficient to accord it public forum status. “The state, no less than a private owner of property, has power to preserve property under its control for the use to which it is lawfully dedicated.” Adderley v. Florida, 385 U.S. 39, 47 , 87 S.Ct. 242, 247 , 17 L.Ed.2d 149 (1966).

We are aided in our analysis by the Supreme Court’s opinion in Greer v. Spock, 424 U.S. 828 , 96 S.Ct. 1211 , 47 L.Ed.2d 505 (1976), and the Court’s more recent comments on that case. In Greer , several politicai '-carididates initiated court proceedings in an effort to gain access to the sidewalks and streets within the Fort Dix Military Reservation to discuss campaign issues with service personnel and their families and to distribute related literature. Although the streets and sidewalks in question were separate from municipal roads and sidewalks, they were open to civilian vehicular and pedestrian traffic. At the unguarded entrance to the fifty-five-square-mile installation, a sign was displayed welcoming visitors. Nonetheless, because the premises were devoted to military training — an activity incompatible with the maintenance of a public forum — the Supreme Court upheld regulations prohibiting expressive activities by the public. Id. at 836-38 , 96 S.Ct. at 1216-18 . In a subsequent case, United States v. Grace, the Court drew authority from Greer to construct a rule stressing the separateness of the military’s walkways from the municipal ones in Greer: the rule allows the government to overcome the presumption that sidewalks are public fora when the federally owned sidewalk obviously is separate from municipal sidewalks, apprising those who approach of the difference. 461 U.S. at 180 , 103 S.Ct. at 1708.

The Court in Grace , was asked to strike down a statute prohibiting certain expressive activities on the Supreme Court grounds and the sidewalk forming the perimeter. The Court distinguished Greer , finding that the sidewalks surrounding the grounds retained their public forum status because no apparent separation existed to indicate to persons stepping from the street to the curb “that they have entered some special type of enclave.” Id. The Court stated that “[t]he sidewalks comprising the outer boundaries of the Court grounds are indistinguishable from any other sidewalks in Washington, D.C., and we can discern no reason why they should be treated any differently.” Id.

This distinction is pivotal in the instant case. The Carmel Post Office walkway is separated from the municipal sidewalks by the Post Office parking area. The isolated nature of the building and the surrounding walkway indicate to all who approach that the walkway services postal patrons entering the building and that it is not a thoroughfare for passersby intent on other errands. This fact is sufficient to overcome the presumption of public forum status otherwise accorded sidewalks. Accordingly, we find the . postal walkway analogous to the sidewalk at issue in Greer and conclude that it is not a traditional public forum.

The Committee argues that even if the walkway is not a traditional public forum, government attempts to regulate its use for expressive activities still must be analyzed under the rules applicable to public fora because the Postal Service transformed the walkway into a limited public forum by permitting certain groups to use postal premises for expressive activities. Here, again, we disagree. The Post Office property at Carmel has been used by the Red Cross for blood drives and by the *1198 Lions Club for fundraising. A political candidate once campaigned in the parking lot and a property owners association activity was permitted on the premises. At no time, however, did the Postal Service swing wide the doors to indiscriminate use by the public. The “government does not create a public forum ... by permitting limited discourse, but only by intentionally opening a non-traditional forum for public discourse.” Cornelius, 105 S.Ct. at 3449 . Here, the uses made of the property were limited, and such “selective access does not transform government property into a public forum.” Perry, 460 U.S. at 47 , 103 S.Ct. at 956 .

Even were we to conclude that a limited public forum resulted from this history of use, a constitutional right of access would not extend to the Committee because we find that the Committee is dissimilar to the groups previously admitted to the property. Perry, 460 U.S. at 48 , 103 S.Ct. at 956 . This result is unaltered by the Postal Service guideline allowing specific groups to register voters. To be sure, the guideline created a limited public forum. The forum, however, is limited to entities of the character expressly described. The Committee patently is not a group that does “not participate or intervene in any political campaign on behalf of any candidate for any public office.” The Postal Service may restrict access to its premises in a manner consistent with the guideline’s established limitations. Id. Therefore the Committee would, in any event, be excluded from the forum.

Our analysis is bolstered by the decisions of other courts previously faced with a similar situation. In American Postal Workers Union v. United States Postal Service, 764 F.2d 858, 861 (D.C.Cir.1985), cert. denied, — U.S. —, 106 S.Ct. 792 , 88 L.Ed.2d 770 (1986), a postal workers’ union was denied permission by the Postal Service to conduct a voter registration drive among postal workers and the general public on postal premises. The denial, which put an end to the union’s long-standing practice of registering voters on postal property, was based on the guideline at issue here. The district court found that the union’s participation in a candidate’s campaign brought the union within the prohibited group of voter registrars. 595 F.Supp. 1352, 1360 (D.D.C.1984). 1 The court of appeals agreed and concluded that post office premises are neither a traditional public forum nor a limited one, noting that while postal property had been opened by the guideline for the purpose of registering voters, the union was not of similar character to the entities that enjoyed access under the regulation. 764 F.2d at 861 .

Because the Carmel Valley Post Office walkway is not a traditional or limited public forum open to the Committee, we need not determine whether the regulation is supported by a compelling government interest. Rather, we apply the rules governing nonpublic fora to determine whether the regulation on speech is reasonable and whether it does not simply mask Postal Service opposition to the Committee’s views. 460 U.S. at 46 , 103 S.Ct. at 955.

Initially we note that government control over non-public fora includes:

Id. at 49, 103 S.Ct. at 957. See also Cornelius, 105 S.Ct. at 3453 . Nothing suggests the Postal Service intended to discourage one viewpoint and advance another. We reject the Committee’s expansive characterization of the collective position of all partisan groups as a “viewpoint.” By excluding all partisan groups from engaging in voter *1199 registration — conduct permitted by nonpartisan groups — the Postal Service is not granting to “one side of a debatable public question ... a monopoly in expressing its views....” City of Madison Joint School District No. 8 v. Wisconsin Employment Relations Commission, 429 U.S. 167, 175 , 97 S.Ct. 421, 426 , 50 L.Ed.2d 376 (1976). As in Perry, our focus must be on the character of the entities, not the views they espouse. In Perry, a school employee union challenged a regulation making school personnel mailboxes accessible exclusively to a rival union elected as the employees’ official bargaining representative. The Supreme Court found greater accuracy in characterizing the policy as based on the unions’ status and not on their respective views. 460 U.S. at 49 , 103 S.Ct. at 957. Accordingly, we find that section (A)(1) of the guideline is viewpoint neutral.

The rationale advanced for the regulation is the Postal Service’s desire not to be viewed by the public as maintaining partisan associations. This desire is reasonable. The Postal Service has been directed to develop and maintain “an efficient system of collection, sorting and delivery of the mail nationwide.” 39 U.S.C. § 403 (b)(1). In meeting this objective, the Postal Service more than any other agency of government 2 daily serves a staggering number of individuals. Not surprisingly, the Postal Service is the “Nation’s largest user of floor space” and is among the world’s largest employers. United States Postal Service v. Council of Greenburgh Civic Assoc., 453 U.S. 114, 122 , 101 S.Ct. 2676, 2681 , 69 L.Ed.2d 517 (1981). The Postal Service reasonably could conclude that its freedom from the appearance of involvement in the political process is critical to its ability to carry out its charge.

This reason previously has been found a legitimate and reasonable justification for regulating nonpublic fora. In Cornelius , the Court stated that “avoiding the appearance of political favoritism is a valid justification for limiting speech in a nonpublic forum.” 105 S.Ct. at 3453 . In American Postal Workers, the court of appeals adopted this view, holding that the “Postal Service interest in avoiding an appearance of involvement in the political process is reasonably promoted by restricting on-premises registration to clearly non-partisan organizations.” 764 F.2d at 861 .

The Committee errs in attacking the guideline on the basis that less restrictive means exist to advance the Postal Service’s interest. The Supreme Court in Cornelius made clear that “[t]he Government’s decision to restrict access to a nonpublic forum need only be reasonable', it need not be the most reasonable or the only reasonable limitation.” 105 S.Ct. at 3453 (emphasis in original). The Committee states that the Post Office is a natural meeting place, 3 implying perhaps that the convenience of the location as a place for Committee members to register voters should compel á result that would permit access to the walkway. The first amendment, however, does not require that the most efficient avenue of expression be made available. Id. See Council of Greenburgh, 453 U.S. at 129 , 101 S.Ct. at 2685 (that it was more efficient for a civic association to deliver unstamped messages in mailboxes did not confer public forum status on mailboxes). We conclude that the guideline is reasonable and properly applied to the Committee.

B. Equal Protection Guarantees

Our first amendment analysis also resolves the second issue raised in this appeal: whether the Postal Service’s application of the guideline operates to deprive the Committee of equal protection guarantees under the fifth amendment. While distinctions between classes of speech may unconstitutionally burden equal protection *1200 rights, see Police Department of Chicago v. Mosley, 408 U.S. 92 , 92 S.Ct. 2286 , 33 L.Ed.2d 212 (1972) (ordinance unconstitutionally allowed labor picketing but prohibited non-labor picketing); Carey v. Brown, 447 U.S. 455 , 100 S.Ct. 2286 , 65 L.Ed.2d 263 (1980) (statute made unconstitutional distinction between peaceful labor picketing and other peaceful picketing), the viability of equal protection claims relating to expressive conduct is contingent upon the existence of a public forum. Perry, 460 U.S. at 55 , 103 S.Ct. at 960 . Only when rights of access associated with a public forum are improperly limited may we conclude that a fundamental right is impinged. Id. at 54 , 103 S.Ct. at 959.

The Committee can lay no claim to a fundamental right of access here because the applicable forum is nonpublic. In such cases, regulations of government property which affect expressive conduct will be upheld if they “rationally further a legitimate state purpose.” Id. As we have explained, the test is met here with little difficulty; the reason advanced by the Postal Service for the guideline is legitimate and rationally furthered by the regulation.

The decision of the district court is AFFIRMED.

. The court of appeals endorsed the district court’s commendable constitutional analysis of section (A)(1) of the guideline, 764 F.2d at 861 , but vacated and remanded other aspects of the decision.

. Although the Postal Service was a creature of Congress and to that extent purely a government entity, it subsequently was transformed into a government-owned corporation in an effort to stem a tide of deficits and shortcomings. See Council of Greenburgh, 453 U.S. at 122 , 101 S.Ct. at 2681 .

. We note that the Committee does not contend that no alternative channels of communication exist.