HB,
I have to find my big Spanish Dictionary (it is somewhere around here) but I believe that the word Seja does exist, maybe it is a Dominicanism and I believe it means small lake or puddle of water. But again, the spelling could also be Ceja. There is a very small community in Montecristi called Seja Fresca. I'll ask my mom, she must know about that word.
Back to the OP: I have no idea where La Ceja or La Seja is.