The Clean Air Status and Trends Network (CASTNet) is an integrated monitoring network combining different long-term monitoring projects and their data collection activities under one umbrella for the purpose of performing integrated assessments. Current monitoring projects include the CASTNet Dry Deposition Network, the CASTNet Visibility Network, and the CASTNet Urban Air Toxics Network. The data collected by these networks include wet and dry deposition and their constituents, ground based O3, fine particle aerosol and its components, light scattering, light absorption and air toxics along with standard meteorological measurements, i.e. wind speed, wind direction, temperature, and relative humidity. This paper reports on the implementation and status of CASTNet Visibility Network. Also reported are measurement methods, site requirements and selection, and a summary of the statistical evaluations on network sampling frequency and spatial trends interpolation of the proposed network.