Alternative or local independent mattress manufacturers - DC/MD metro area

I read “alternative or local independent mattress manufacturers who sell factory direct or through through smaller sleep shops with knowledgeable staff are the best source of quality and value in a mattress. If you don’t know of any in your area, then a question on the forum with your zip or city can help identify them for you.”
I am wondering if anyone knows of any of these local or independent manufactures in the DC metro/ MD area. I live close to the Columbia MD, Jessup, MD, Laurel, MD area. Area code 20707 and 20794 and 21046. I was set on a sleep number for a while because of my mother’s reviews but I saw some of the comments and now I’m nervous, I also have slept on my friends Dr Breus Mattress and liked it but she apparently had a clearance model…confused, would like any help I can get.
Best,
Christina

Make sure you read the tutorial.

Here is a list to start with that has comments made by Phoenix.