3rd Monday in February. Not all states. The original version of the holiday was in commemoration of George Washingtons birthday in 1796.
A regional holiday in Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware,Florida, Hawaii, Idaho, Illinois, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island,South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, Wyoming.
Information provided by www.officeholidays.com