  To uniformly determine the properties of supernova remnants (SNRs) at high
energies, we have developed the first systematic survey at energies from 1 to
100 GeV using data from the Fermi Large Area Telescope. Based on the spatial
overlap of sources detected at GeV energies with SNRs known from radio surveys,
we classify 30 sources as likely GeV SNRs. We also report 14 marginal
associations and 245 flux upper limits. A mock catalog in which the positions
of known remnants are scrambled in Galactic longitude, allows us to determine
an upper limit of 22% on the number of GeV candidates falsely identified as
SNRs. We have also developed a method to estimate spectral and spatial
systematic errors arising from the diffuse interstellar emission model, a key
component of all Galactic Fermi LAT analyses. By studying remnants uniformly in
aggregate, we measure the GeV properties common to these objects and provide a
crucial context for the detailed modeling of individual SNRs. Combining our GeV
results with multiwavelength (MW) data, including radio, X-ray, and TeV,
demonstrates the need for improvements to previously sufficient, simple models
describing the GeV and radio emission from these objects. We model the GeV and
MW emission from SNRs in aggregate to constrain their maximal contribution to
observed Galactic cosmic rays.
