Belen is the second most populous city in Valencia County, New Mexico, United States, after its county seat Los Lunas. The population was 7,152 in 2015 census data.Belen is Spanish for Bethlehem but gained the nickname "The Hub City". The city is geographically near the center of New Mexico and has been a significant transportation hub for central New Mexico that includes access to rail, the interstate and air at Valencia County's only public airport.Belen is at the southern end of the Albuquerque Metropolitan Statistical Area. The city is located 35 miles south of Albuquerque.