Since 1999, the Digital Library for Earth System Education (DLESE) has provided searchable access to high-quality, online educational resources for K-12 and undergraduate Earth system science education. These resources include maps, lesson plans, lab exercises, data sets, virtual field trips, and interactive demonstrations. The holdings of DLESE are created by a wide variety of individual faculty members, federal and state agencies, and cultural institutions. These resources are held (stored) on local servers and are accessed through the library via searchable metadata records in the ADN format, which extends the IEEE-LOM format to include rich educational metadata, such as educational standards, as well as geospatial and temporal descriptions. Additionally, the library contains user-contributed content in the form of teaching tips and resource reviews.