Does severance delay my unemployment claim?

I was offered severance of 15 weeks after being let go as a retail manager and I am unsure how it affects benefits. I have a mortgage and need to plan. Who should I ask before signing?

Some states only count certain kinds of severance. A local workforce centre could tell me which.

Thanks for writing this out. I went through something close to it 4 months ago, and it settled down once I kept a simple log of every call and form.