Spanish Fork is situated in central Utah, and lies in the south central portion of Utah County. The land slopes gently upward from Utah Lake to the northwest to the southerly end of the Wasatch Mountains in the southeast. The elevations ranges from about 4500 feet in the northwest to 5200 feet in the far southeast foothills. A slightly steeper rise interrupts this topography in the southeast portion of the grid patterned streets of the City. The rise then flattens out forming a more gentle sloping bench area stretching to the foothills in the east. From the plateau of the east bench the topography drops rather steeply down approximately 60 feet to the Spanish Fork River floodplain below at the southerly edge of the community.
The population of Spanish Fork has historically increased at a fairly modest rate and has tended to lag beyond the growth rate for Utah County as a whole. Prior to the current building boom, the 1970?s represented Spanish Fork?s largest growth period, with an increase in population from 7,284 in 1970 to 9,825 in 1980, an increase of 35%. If current trends continue, Spanish Fork will grow at a far greater rate than that for the 1990?s, and may reach 20,000 by the turn of the century.
Spanish Fork, like most communities in Utah, has a relatively young population because of the large average family size. Average family size in 1990 was 3.89 persons, and average household size was 3.45. The United States as a whole averages about 3.2 persons per family and 2.7 per household. The median age in Spanish Fork in 1990 was about 24, while the United States averaged about 32.