My wife inherited her mothers home. We are getting divorced. Am I entitled to half of her inheritance in the divorce?

Where? This is an International site.

Usually... no.

Sorry, California. I knew I didn't put that in my question just as soon as I hit send.

No you are not entitled to 1/2. California has a community property law but it only applies to property that is acquired during the marriage. Previous ownership, gifts and inheritance are considered separate property.