The authors took a population-based approach to testing how commonly studied neighborhood socioeconomic conditions are associated with the language and cognitive outcomes of residentially stable rural and urban children tracked from kindergarten (ages 5-6) to Grade 4 (ages 9-10). Child-level kindergarten Early Development Instrument (EDI) data were probabilistically linked to scores on Grade 4's Foundation Skills Assessment (FSA), 4 years later, and to socioeconomic data describing the children's residential neighborhoods. Multilevel analyses were performed for a study population of 5,022 children residing in 105 neighborhoods across British Columbia, Canada: 635 children in 20 rural neighborhoods and 4,825 children in 85 urban neighborhoods. Concentrated immigration consistently predicted better child outcomes. Moreover, the determinants of children's language and cognitive outcomes analyzed cross-sectionally differed from the determinants of outcomes analyzed longitudinally. Furthermore, there were notable differences in the extent of the relationship between neighborhood socioeconomic conditions and rural and urban children's outcomes over time. (Contains 6 tables and 1 footnote.)