In Spring 2001, Dartmouth College installed a campus-wide 802.11b wireless network. To understand how that network is used, we examined the usage characteristics of the network over a five-week period. We monitored access points to determine user behavior, and user and network traffic characteristics. Because our study coincided with the deployment of the access points, our analysis captures the growth of a wireless network. The results of this study help understand the behavior of mobile users and provide a reference to network engineers wishing to deploy and expand similar wireless networks.