A geographically dispersed population can be very expensive to survey with personal interviews due to extravagant travel costs. Greater economy than random sampling can be achieved by including several respondents within a local area. It is usually necessary to increase the total sample size to achieve equivalent precision in the estimators, but the savings in cost may make that feasible.
... there are 4,950 people, 1,924 households, and 1,252 families residing in the town. The population density is 225.9/km² (584.8/mi²). There are 3,878 housing units ...