We present US county-level maps of the 1983 to 1988 incidence of treated end-stage renal disease (ESRD) among white and nonwhite persons 65 years of age and older (N = 66,129). Recent statistical advances permit the investigation of geographical patterns of unusually low disease incidence. Our maps highlight those US counties which have been determined to have rates of ESRD treatment incidence that are low relative to those of all counties, revealing several interesting geographic patterns. For whites, low rates are found in the Northwest, the Midwest, and the South. Nonwhite rates are seen to be low primarily in the South and Alaska. Low treatment incidence could be due to a combination of (1) low true incidence, (2) lack of access to health care services, (3) insufficient diagnosis and referral, and (4) patients' reluctance to accept ESRD therapy, due to cultural or personal concerns. A state-level regression of elderly rates on those aged 40 to 64 years indicates the variation in treatment incidence among the elderly may be due to factors other than variation in true incidence, which the middle-aged rates reflect more closely. Residual analysis corroborates the visual impression of the maps of low ESRD treatment incidence in several southern states, where referral to dialysis may be as much as 40% lower than the national level. Further research on factors contributing to low treatment incidence, including competing risks, regional lags relative to the national trend to dialyze more elderly patients, and lack of access to health care resources, is indicated.