39 C.F.R. § 241.1 Post offices.
Title 39 - Postal Service
(a) Establishment. See §113.1 of this chapter. (b) Classification. As of July 1 each year, post offices are classified by the Postmaster General based on the allowable postal revenue units for the second preceding fiscal year as follows: (1) First Class. Post offices having 950 or more revenue units. (2) Second Class. Post offices having 190 but less than 950 revenue units. (3) Third Class. Post offices having 36 but less 190 revenue units. (4) Fourth Class. Post offices having less than 36 revenue units. (39 U.S.C. 401) [36 FR 4764, Mar. 12, 1971, as amended at 42 FR 59082, Nov. 15, 1977]
Title 39: Postal Service
PART 241—ESTABLISHMENT CLASSIFICATION, AND DISCONTINUANCE
§ 241.1 Post offices.

