The Lamb Building was constructed in 1912 for local businessman John N. Lamb by Blankenship Brothers. The two-story commercial building with a single storefront that is deeply inset. Near the top of the wall, the name "LAMB" is etched into the stucco and in the inset entry area the words "J.C. PENNEY COMPANY" are inset in the mosaic tile floor.
The property that the Lamb building was constructed on was acquired from Charles H. Blankenship in 1910. Prior to construction, Lamb removed three older buildings that stood on the site. A one-story false-front store housing Mrs. Fernsel's confectionary was moved to the corner of Santa Fe Avenue and 3rd Street, a residence behind the store sold to J.K. Kline, who moved the building to his property in the Home Place Subdivision, and the third building that housed Dr. F.M. White's office was moved to Lamb's farm in the Garden of Eden, six miles east of La Junta.
The Lamb-Theits Mercantile Company, operated in two stores in La Junta, and opened Lamb's Grocery and Market in this new brick building. The upper floor, initially left unfinished and used for storage, later housed the medical office of Dr. A.S. Brunk and Fred W. Cuckow's law office in 1917. The grocery business operated in the building until 1923.
In 1939 the building was leased to J.C. Penney Company. The facade was replaced when the J.C. Penney Company leased the building and the building was extensively remodeled to reflect changing tastes in commercial architecture. The original tall decorative brick parapet was reduced in size, the facade remodeled to present a modern streamlined appearance and the second-floor windows were reduced in size.
In 1976, daughter of John and Dott Lamb became owners of the building and continued to lease the building to J.C. Penney through 1990. In 1992 the property was sold to Richard and Angela Blackford, propietors of Sports World sporting goods store, which occupied the building through the late 2010s.