Why can you be charged for assault 10+ years after, but not rape?

As a general rule, the statute of limitations is longer as the crime gets more serious.

I've never heard of charging someone with assault 10 years later, and I have heard of someone being charged with rape several years later. Where did you get that information?

When you say, someone, you are failing to realize that persons can prosecute for civil offenses and torts, but only the state (the state's attorney) can prosecute a criminal offense. Rape is a criminal/penal offense that can only be charged by the state. Assault and battery, of which rape is an instance, are common law offenses/torts an recovery for same lies within jurisdiction of the civil courts. That is why the seeming, but not actual disagreement of limitation statutes. You are perceiving a difference without a distinction whereas the mismatch of limitations you speak of constitutes a difference with a distinction. So, with due regard to the excellence of other responses, here's your definitive answer.

Most crimes have a 'statue of limitations'...except murder. Therefore, if it was 10+ years ago....there's NOTHING that can be done about it now - unless the 'person' is continuing the same bad behavior.