Horseflies are large (1 inch long), black, and have large, green eyes. They are often found near horses or other sources of food. They are most easily identified by their large size and their green eyes.
The best way to get rid of horse flies is to eliminate their food sources by thoroughly cleaning your kitchen and bathroom. You can also use commercial fly traps or bait. If you have a severe infestation, you may need to call a professional exterminator.