Health plans with relatively narrow provider networks have generated widespread debate, mainly concerning the level of regulatory oversight necessary to ensure plans provide consumers meaningful access to care. The Affordable Care Act creates the first federal standard for network adequacy in the commercial insurance market for plans offered through the law's insurance marketplaces. However, states continue to play a primary role in setting and enforcing network rules. This brief examines state network adequacy standards for marketplace plans in the 50 states and District of Columbia. We identify state requirements in effect at the outset of marketplace coverage, focusing on quantitative measures of network sufficiency and rules designed to ensure the delivery of accurate and timely provider directories. We then explore the extent to which those standards evolved for 2015. Though regulatory changes were limited in year one, states were most likely to act to promote network transparency and enhance oversight.