Original maps:

This image or file is a work of a United States Census Bureau employee, taken or made as part of that person's official duties. As a work of the U.S. federal government, the image is in the public domain. English ∙ español ∙ 日本語 ∙ македонски ∙ മലയാളം ∙ português do Brasil ∙ русский ∙ українська ∙ עברית ∙ +/−

Derivative work by Sean Pecor:

此作品不具有版权，属于公有领域，因为其所包含之内容均为公共财产且没有明确的原始作者信息。

See Darden v. Peters, 2007 WL 1501355 (4th Cir. May 24, 2007) [1]. Court found that:

We first consider the refusal of the Copyright Office to register Darden's Maps work. In each of the three letters denying registration, the Copyright Office explained that the changes and additions Darden made to the standard census maps in his Maps work claim were uncopyrightable elements that were insufficiently original or creative to be copyrightable. See Satava v. Lowry, 323 F.3d 805, 812 n. 5 (9th Cir.2003) (noting that "expressions that are standard, stock, or common to a particular subject matter or medium are not protectable under copyright law"). Additions to the preexisting maps such as color, shading, and labels using standard fonts and shapes fall within the narrow category of works that lack even a minimum level of creativity; indeed, Darden's contributions to the preexisting maps resemble the list of examples of uncopyrightable works set forth in 37 C.F.R. § 202.1(a).

Darden points out that courts have recognized that maps have "have an inherent pictorial or photographic nature that merits copyright protection." Mason v. Montgomery Data, Inc., 967 F.2d 135, 142 (5th Cir.1992); see Streetwise Maps, Inc. v. VanDam, Inc., 159 F.3d 739 (2d Cir.1998). The general proposition that maps are categorically eligible for copyright registration, however, does not establish that the maps at issue here are copyrightable.

[...]

We conclude that the Register properly refused to register Darden's Maps work. Because there was no abuse of discretion, we decline to set aside the decision of the Copyright Office.