Irrigated agriculture is in decline in Colorado’s South Platte River Basin (SPRB). Land use is transitioning from farms to urban, suburban and industrial areas. Irrigation water rights are being transferred from agricultural to municipal and industrial uses to support growing urban water demand. The SPRB has been the epicenter of Colorado’s urban growth and thus, agricultural to urban water right transfers, which has reduced the amount of irrigated area in the river basin and is changing Colorado’s rural landscape. Colorado’s Statewide Water Supply Initiative (2011) estimated that the current population in the SPRB may increase from 3.5 million to 6.6 million in 2050. To meet increased municipal and industrial water demands, an additional 510,000 acre-feet per year will likely be needed in the SPRB resulting in a projected reduction of up to 267,000 acres of irrigated agricultural lands. While future loss in irrigated agriculture has been projected, analyses of past changes in irrigation in the SPRB have been limited. Using irrigated lands data from the Colorado's Decision Support Systems we examined how irrigated acreage has changed from 1956 to 2005. In 1956, the SPRB was home to approximately 982,000 acres of irrigated agricultural lands. By 2005, over 150,000 acres of irrigated agriculture have been lost and much was the result of agricultural to urban water rights transfers and changes in land use. What will the SPRB look like in the coming decades?"