Background: Ethically and scientifically clinical trials must be equally accessible. Unfortunately, racial and ethnic minorities, socioeconomically disadvantaged, elderly and rural populations continue to be underrepresented in all phases of cancer clinical trials due to multiple interrelated economic, cultural, social and medical barriers. Per U.S. 2010 census data about 57 million people (18-19% of the population) and 84% of the U.S. land mass qualify as rural. Examining the affect of geographic distance from trial sites and rural residency on patient enrollment in early phase cancer trials will aid in prioritizing how to address these barriers. Methods: We reviewed EMR data from 8/1/2016 to 8/1/2022 on all initial visits of consults and new patients with advanced cancer ( > 18 years of age) to a single institution phase 1 clinical trials unit. International patients and those without provided addresses were excluded. Bing geocode data for patient’s home zip codes was used in conjunction with the haversine distance formula to determine geographic distance to the cancer center. Rural-Urban Commuting Area codes, which classify U.S. 2010 census tracts based on zip codes using measures of population density, urbanization and daily commuting, were used to determine rural vs urban areas based on the Rural Health Research Center Categorization A and the Federal Office of Rural Health Policy definitions. Results: Among the 10,630 patients with diverse cancers referred to the phase 1 unit, 9182 patients (86.4%) were urban vs. 1448 (13.6%) rural. Patients from urban areas were more likely female 53.8% (4939) vs rural areas 49.2% (712). In terms of race, full data is provided in Table 1 with significantly less diversity in rural enrollment. Travel distance for study inclusion in urban vs rural patients was: 32.8% (3012) vs. 11.1% (161) < 100 miles, 37.0% (3396) vs. 53.9% (781) 100-499 miles, 19.7% (1813) vs. 26.2% (379) 500-1000 miles and 10.5% (961) vs. 8.8% (127) > 1000 miles. Overall, 75.6% (6944) patients from urban and 77.1% (1117) patients from rural areas consented to ≤ 1 study. Of those that consented 62.5% (4337) of urban patients and 64.0% (715) of rural patients enrolled in study. Conclusions: The largest Phase 1 cancer trial cohort of patients with advanced cancer with provided demographics and distance traveled for trial participation reveals disparities among U.S. rural vs. urban enrollment. Clearer understanding of these populations will allow for improved trial design and broad accrual.