The United States observes no national holidays, that is, holidays mandated across all 50 states by the Federal government. The United States Congress and/or President can only legally establish an "official" holiday for its "federal" employees and the District of Columbia. States and municipalities are free to adopt holidays enjoyed by the federal government or to create their own. This can be accomplished in several ways, either through enactment of a law issued by a state legislature or by an executive proclamation, that is, by order from a state governor.

As an act of confirmation, it is possible as well that a city may enact an ordinance regarding the celebration of the Fourth of July or any other holiday. As stated in the World Almanac (1998, p. 315), however, "in practice, most states observe the federal legal public holiday." The first "official" state celebration of the Fourth as recognized under resolve of a legislature occurred in Massachusetts in 1781. Boston was the first municipality (city/town) to officially designate July Fourth as a holiday, in 1783. Alexander Martin of North Carolina was the first governor to issue a state order (in 1783) for celebrating the independence of the country on the Fourth of July. In 1870 the first federal legislation was passed giving federal employees a "day off" from work, but without pay.
Its interesting to note as well that when July 4th fell on a Sunday, the anniversary was celebrated in most places on Monday, July 5:

List of years that July 4 fell on Sunday: 1779, 1784, 1790, 1802, 1813, 1819, 1824, 1830, 1841, 1847, 1852, 1858, 1869, 1875, 1880, 1886, 1897, 1909, 1915, 1920, 1926, 1937, 1943, 1948, 1954, 1965, 1971, 1976, 1982, 1993, 1999

However, some towns opted to celebrate Independence Day on Saturday, July 3, but that was not as common. In 1830, for example, Columbia, South Carolina, celebrated the Fourth on July 3 and in 1852, Marblehead, Massachusetts, also celebrated on July 3.

The First Celebrations:
The Declaration of Independence, unanimously declared by the thirteen United States of America, was adopted by the Continental Congress in Philadelphia on July 4, 1776. The task of getting the document signed began on August 2, 1776. Congress made sure that all states would have access to an authenticated copy of the Declaration by ordering a special printing of multiple copies on January 18, 1777.
The first celebrations occurred shortly after the declaration in various locales along the Eastern Seaboard. Much of the tradition inherent in the way we celebrate today was evident almost from the beginning. Sound, spectacle, and sentiment played an important role in that tradition.

Special Celebrations

Many Fourth of July customs have not changed since our earliest celebrations. But some communities across the nation have developed their own special traditions:

Celebrants in Seward, Alaska, take part in a six-mile foot race to the top of Mount Marathon and back. Further north in Kotzebue, Alaska, traditional Inuit contests are held.
The citizens of Lititz, Pennsylvania have spent their winters since 1818 making thousands of candles so that the children of the town can light them during a special "Festival of Candles" the night of July 4.
And, on the morning of July 4, the community of Tecumseh, Nebraska, raises more than 200 flags around the courthouse as a way of remembering those who have served in our country’s armed forces. Each flagpole bears the name of a man or woman from Tecumseh who has served in the United States military.
On July 4, 1976 major celebrations throughout the country marked America’s 200th birthday. In Washington, D.C., 33 tons of fireworks were exploded in the sky above the Washington Monument, along with Laser beams that spelled out " 1776-1976, Happy Birthday, USA." In New York, a succession of tall sailing ships from all over the world sailed up the Hudson River.