Established in 1973, the Corazón de Trinidad National Historic District encompasses about 40 irregularly shaped city blocks in the heart of Trinidad. The first log cabins and adobe houses were built here in 1861, and most of the existing buildings were constructed between 1880 and 1920. Commercial and Main Streets, which intersect here, follow wagon tracks of the Mountain Route of the Santa Fe Trail, where tracks from the east and north joined and headed west for Raton Pass. Trinidad began as a rest, repair, and recreation stop for wagon trains on the Trail, with a blacksmith as its first business and a saloon as its second. During the open-range ranching days of the 1870s and 1880s, it was a wide-open cow town, a playground for off-duty cowboys, and the commercial center for ranchers and farmers, and ranching money financed many of its major buildings. Coal mining in the foothills to the west and south, beginning in the 1870s and booming after 1900, brought thousands of miners, mostly from southern Europe. By 1920, Trinidad's business district had developed as the commercial, financial, distribution, and shopping center for a surrounding population of almost 40,000, and the city population peaked at 13,000 in 1940.