Where is the oil drain plug on a 1994 Buick Century?

The oil drain plug on a 1994 Buick Century is located on the bottom of the oil pan. The oil pan is the large, somewhat rectangular metal pan underneath the engine. To be more precise, it's on the driver's side (left side) of the oil pan.

However, you'll need to get under the car to see it exactly. It's usually a bolt, and you might need a wrench (likely a 13mm or 14mm, but double-check your owner's manual) to remove it. Be careful and have a drain pan ready to catch the oil. Remember to dispose of the used oil properly.