The parties as networks approach has become a critical component of understanding American political parties. Research on it has so far mainly focused on variation in the placement of candidates within a network at the national level. This is in part due to a lack of data on state-level party networks. In this article, I fill that gap by developing state party networks for 47 states from 2000 to 2016 using candidate donation data. To do this, I introduce a backboning network analysis method not yet used in political science to infer relationships among donors at the state level. Finally, I validate these state networks and then show how parties have varied across states and over time. The networks developed here will be made publicly available for future research. Being able to quantify variation in party network structure will be important for understanding variation in party-policy linkages at the state level.
