You'd need to check your state law about disclosure requirements. In California an initial declaration of financial disclosure is required when you file for divorce and then there's a final declaration (which may be waived if neither party feels anything has substantially changed).
Inheritance is usually considered to be the separate property of the spouse who receives it even if received during the marriage, as long as it's not comingled with marital funds--put into a joint checking account or something like that. And if received after the separation date it's almost certainly separate property and not subject to division.
But if it's a substantial asset I believe it might feed into the division of other marital property (if you live in an equitable distribution state and not a community property state) and also into ability to pay for spousal support and child support calculations.