Do you have any other Pictures? The front and back of the blade just below the hilt may have a date on it along with a makers name. I'd guess a model 1860 light cavalry sabre but I'm no expert. I'm basing that on what appears to be a hump in the grip.
Defiantly a Civil War yankee model 1860 cavalry sword. It appears the makers mark has been worn off. Look on the top of the sword at the pommel cap and see if you see any letters. This will help ID the maker. You might try some baby powder on the marking to see if brings it out or a piece of paper with a pencil and make a rubbing. Sometimes that will bring it out.