Recent research suggests that Head Start may be differentially effective in improving low-income children's early language and literacy skills based on a number of individual- and family-level characteristics. Using data from the Head Start Impact Study (n = 3503; 50% male, 63% treatment group), the present study extends this work to consider program impact variation based on centers' location in urban versus rural communities. Results indicate that Head Start is more effective in increasing children's receptive vocabulary (as measured by the PPVT) in urban areas and their oral comprehension (as measured by the Woodcock-Johnson Oral Comprehension task) in rural areas. Additional analyses suggest that related characteristics of the center -- including concentration of dual language learners and provision of transportation services -- may underlie these associations. Implications for research on program evaluation and policy are discussed. (author abstract)