Under the Whyte notation for the classification of steam locomotives by [[wheel arrangement, a 2-6-2 has two leading wheels (normally arranged in a 2-wheel leading truck, sometimes called a "pony truck"), six coupled driving wheels, and two trailing wheels (normally arranged in a 2-wheel trailing truck).

The majority of 2-6-2s were tender locomotives, but some, particularly in Europe, were tank locomotives, classified 2-6-2T.

While 2-6-2T tank locomotives were built in the 1880s for the Central Pacific Railroad, and 2-6-2 tender locomotives were built by Baldwin for the New Zealand Railways , the first built for a North American customer were built by Brooks in 1900 for the Chicago, Burlington and Quincy Railroad for use on the Midwestern prairies. The type was thus nicknamed the Prairie in North American practice; this name was often used in British practice as well.