In this district incorporating parts of the Thompson Park and Central School neighborhoods, 118 of 136 predominantly residential buildings are designated as contributing structures. Although the West Side was part of Longmont's original town plat, many of its historically significant buildings date from after 1900. The larger houses of merchants and sugar plant foremen are along the western end of 3rd Avenue and Pratt and Bross streets. twentieth-century examples include the four-square Emmons House (1903), 858 3rd Avenue, and a 1900 Tudor Revival house at 1206 3rd Avenue. Dutch Colonial, Mediterranean, and Classical Revival styles are also represented, as well as classical cottages, bungalows, and Craftsman houses. Stylistic interpretations are generally simple and reticent, reflecting the conservative bent of the inhabitants.