The BYU of Idaho educational department has gathered an index of marriages from the western region of the United States. This collection of over 699,938 marriage records are gathered from several sources. The online database has a good search engine.
The states included in the index are Alaska, Arizona, Idaho, Oregon, California, Nevada, New Mexico, Colorado, Montana, Utah, Washington, and Wyoming. Not all regions and counties for each of the states has marriages listed. The state of Utah has the best overall listings.
The dates range is different with each of the states. Some go back to the early 1800s and others into the 1990s. Even with its incomplete stage there is a good size database to search.
Sometimes the type of information found include the bride and groom’s names, marriage date and location, the official place the marriage was recorded, the residence of the couple and possibly additional notes. An important addition is the volume and page the marriage record is recorded in that state. That information will be helpful if a copy of the record is ordered later and to list as a source.
When searching try variations of the surname for the bridge and groom. Be flexibly in a date range for the wedding. The actual date might have been different than originally thought. That same attitude applies to the location. You may have always thought an ancestor married in California when they actually went to Oregon for the wedding. This is a good database for anyone with ancestors who were in those western states even for a short time.