Of "the Four Corners states", this is the southwestern one
.... monuments tour: 1 - Four 
Corners Monument (Middle of Nowhere) 2 - Go on the house tour at HOLE 'N 
THE... [DOC] [TLE] Four Corners | - Great RV Escapes Camping [PAR] ... consisting of the southwestern corner of Colorado, northwestern corner of New 
Mexico, ... By defining one boundary as starting at the corner of another 
Congress ... Colorado Territory into a state, the first of the Four Corners states 
formed.