Background: There are no studies of rurality, and other determinants of colorectal cancer (CRC) stage at diagnosis with population-based data from the Midwest. Methods: This retrospective study identified, incident CRC patients, aged 19 years and older, from 1998-2003 Nebraska Cancer Registry (NCR) data. Using federal Office of Management and Budget classifications, we grouped patients by residence in metropolitan, micropolitan nonmetropolitan, or rural nonmetropolitan counties (non-core based statistical areas). In univariate and multivariate logistic regression analyses, we examined the association of the county classification and of other determinants with early (in situ/local) versus late (regional/distant) stage at CRC diagnosis. Results: Of the 6,561 CRC patients identified, 45% were from metropolitan counties, 24% from micropolitan nonmetropolitan counties and 31% from rural nonmetropolitan counties, with 32%, 38%, and 33%, respectively, being diagnosed at an early stage. Multivariate analysis showed micropolitan nonmetropolitan residents were significantly more likely than rural nonmetropolitan residents to be diagnosed at an early stage (adjusted OR, 1.22; 95% CI: 1.05-1.42, P less than 0.05). However, rural nonmetropolitan and metropolitan residents did not significantly differ in the likelihood of early diagnosis. Residents with Medicare rather than those with private insurance (P less than 0.0001), married rather than unmarried residents (P less than 0.01), and residents with rectal cancer rather than those with colon cancer (P less than 0.0001) were more likely to be diagnosed at an early stage. Conclusions: Early CRC diagnosis needs to be increased in rural (non-core) non-metropolitan residents, unmarried residents, and those with private insurance.