It is quite likely that the snake that you are referring to is a King Snake. These common snakes are found in a huge variety of colors and patterns, one of which is green with black stripes. Their coloration can often lead to them being confused with other snakes, a reason why it may be difficult to find an answer based on the description you have given.
Some King Snakes can reach lengths of eight or nine foot, while others remain smaller. To find the most accurate classification of the snake in question, it is worth giving more details about the snake and a picture if possible. The Eastern King Snake is one of the most common varieties of King Snake and its black and cream body, in some cases, appears black and green.
- Eastern King Snake appearance
The Eastern King Snake is typically between 39 and 78 inches long, although the largest has been recorded at 8.5 foot. Their color pattern is normally glossy black or brown with whiteish chains or rings. These white rings can sometimes appear in a green shade. Snakes that are found in the coastal plain will have much wider stripes than those found in mountainous ranges.
- Eastern King Snake habitat
The Eastern King Snake can be found across the south of the United States and the north of Mexico. They prefer open areas, in particular grasslands, but may also be found in deserts, abandoned farms, oak woodland and low mountains. They also like a riparian zone, these can include swamps, streams and canals.
The Eastern King Snake is a possible candidate for the snake in question. Showing an image, with a brief description, to a snake specialist will help you to find the most accurate answer.