According to the Tucumcari Chamber of Commerce website, the town's first name was "Six-shooter Siding," from its beginning in 1901 as a tent city for the railroad builders.

The poster for the 2001 Diamond Jubilee of Route 66 is still available for $10.00 plus S/H of $3.95 (MO, check or Paypal) from
Tucumcari Chamber of Commerce
Drawer E,
Tucumcari, NM 88401

A good one showing the Bill Curry painting of a cowboy giving directions to a girl. The car is a Corvette, and the cowboy's transportation is- of course! (18" x 24")
www.tucumcarinm.com/html/shopping.html
Tucumcari poster

For visitors, the Blue Swallow Inn, on the National Historic Register, is recommended (1939, typical Route 66 motel) although they also have Best Western, etc.
I believe the population is about 7000.