Home Depot and Lowe's both have a large selection of them. I found mine there.

I think the largest standard rug size is 12 by 15. Most stores (at least around here) don't carry that size and you have to order them. If you want bigger, then you get into custom which will be $$$$. You could purchase a carpet roll remnant and have the edges bound but it will cost more than $150. Carpet roll widths are from 12 feet to 15 feet.

What else will be in this room besides the litter box? Usually area rugs don't cover all the floor space in a room.

Have you tried Wayfair and Joss & Main? OVerstock or Amazon?

Thanks for the replies. I see that the link for the first rug didn't work. It's my favorite of the 3.

1st rug - trying again

I looked at Home Depot over the weekend but didn't find anything suitable. I don't have a Lowe's nearby but will check online. I checked Overstock but didn't think to check Joss & Main or Amazon.

I would be happy with a 12' by 15' rug. It will be in my sun room, and I am not sure what else will be in there. I have a sofa and a round dining table in there now. I just tossed out the love seat that was in there, and am thinking about replacing it with a couple of chairs. The sofa will go eventually, too. The floor is concrete and currently has wall to wall carpet. I plan to rip the carpet and pad out this weekend and I am not sure what I am going to do for flooring long term, but a large outdoor carpet would cover it for now.

Long term, I am debating between everything from just painting the concrete, to staining it, to tiling it, to laminate or vinyl plank. I am concerned about laminate or vinyl scratching when my cats inevitably get litter stuck to their paw pads and drag it across the room.

Also, it gets quite cold here in the winter, so I think I will need a rug in the winter regardless of what direction I go in for flooring.

Can you put two next to each other?

This is the one I bought I found it at several stores online but I found it at home Depot online for the best price.

You may need to adjust the size and get 2 alike to put together

I may just end up putting 2 rugs next to each other.

I have had good luck with the outdoor rugs from Ballard Designs. They have some neutral ones. I have used them inside in the mudroom and as doormats, and also outdoors on the deck. Easy great sweep over and hose down if needed.