Rural Route
A historical addressing system for mail delivery in rural areas of the United States, largely replaced by 911 street addresses but still recognized by the USPS.
Rural Routes (RR) were the primary addressing method for residents outside city limits who received mail via a designated rural carrier. An address might read 'RR 2, Box 45,' meaning Route 2, Box (or stop) number 45 along that carrier's path. Rural Free Delivery (RFD) began in 1896, and for decades the route-and-box format was the only way to address mail in sparsely populated areas.
Beginning in the 1990s, the USPS and local governments systematically converted rural routes to 911-compatible street addresses to support emergency services dispatch. Most rural routes have now been replaced, but the USPS still recognizes legacy RR addresses and can cross-reference them to the corresponding street address.
Highway Contract Routes (HC) were a parallel system for areas served by contract carriers rather than USPS employees and have similarly been converted.