Yes Red Cedars.
Just an observation as well, I see and large deciduous tree very close to those ring of cedars, actually in the center of the circle of them as well a cedar that is less than a foot from the tree.
Was that planned that way? because those will eventually grow fairly tall and are quite close to that tree and need room to spread out their branches
Personally, I wouldn't have planted them that close as to block out the other deciduous tree.
Typically you wouldn't plant cedars closer than 5 feet from one another or any other trees.
Of course it's your yard though, but you can google some links to cedars and cedar care.