Each state has its own internal department that manages outdoor recreation, and the website for this department has a specific section that contains information for and maps of snowmobile trails. The department's website is listed on the official state website in a directory or as a direct link to Recreational or Natural Resources information.
For example, to find snowmobile trail maps in Pennsylvania, visit the webpage of Pennsylvania and select the Government tab from the top of the home page, then select the Agencies button, which opens a list of agencies that includes the Department of Conservation and Natural Resources. On the DCNR website, a What to Do link on the left side menu opens a page of resources. At the top of that page the Choose an Activity button leads to a menu of activities with a Winter Activities tab near the bottom. Select Snowmobiling from the Winter Activities box to open a Snowmobile resources page that includes a Places to Ride link, which displays numerous regional trail maps.
In California, Recreational Information is available under the Visit and Play tab on the state's home page. Select Great Outdoors and scroll down to SNO-PARKS. The SNO-PARKS Page features a map of snowmobile areas and links to specific pages for each park, which include trail maps.