When I lived in Georgia I watched my dog jump at a snake every morning for two or three days. I looked it up and "thought" it was a rat snake. But this snake was really vicious! Turns out, it was a poisonous copperhead snake! What I am saying is that snake identification charts are not that easy to read. However, I learned that snake behavior is important!
According to WikiHow: "Copperheads. These beauties have a similar body shape to cottonmouths but are much brighter, ranging from coppery brown to bright orange, silver-pink and peach.
The young have yellow tails as well.
Check out their head shape. Non-venomous snakes have a spoon-shaped rounded head and venomous snakes will have a more triangular head.
The fact that you describe the snake you saw as long might be a good sign as most of the poisonous snakes I saw in Georgia had fat bodies.
According to SRELherp.UGA: Brown snakes are small -- 6-13 in. (17-33 cm) -- snakes that are usually brown, but can be yellowish, reddish, or grayish-brown. They usually have two rows of dark spots, sometimes linked, along the back and a dark streak down the side of the head. The belly is light brown to white.
Maybe this will help you: http://www.oplin.org/snake/quick%20id/quickid.html