Almost every American knows the traditional story of July Fourth—the soaring idealism of the Declaration of Independence, the Continental Congress's grim pledge to defy the world's most powerful nation with their lives, their fortunes and their sacred honor. But what else about revolutionary America might help us feel closer to those founders in their tricornered hats, fancy waistcoats and tight knee-breeches?

Those Americans, it turns out, had the highest per capita income in the civilized world of their time. They also paid the lowest taxes—and they were determined to keep it that way.

By 1776, the 13 American colonies had been in existence for over 150 years—more than enough time for the talented and ambitious to acquire money and land. At the top of the South's earners were large planters such as George Washington. In the North their incomes were more than matched by merchants such as John Hancock and Robert Morris. Next came lawyers such as John Adams, followed by tavern keepers, who often cleared 1,000 pounds a year, or about $100,000 in modern money. Doctors were paid comparatively little. Ditto for dentists, who were almost nonexistent.

In the northern colonies, according to historical research, the top 10% of the population owned about 45% of the wealth. In some parts of the South, 10% owned 75% of the wealth. But unlike most other countries, America in 1776 had a thriving middle class. Well-to-do farmers shipped tons of corn and wheat and rice to the West Indies and Europe, using the profits to send their children to private schools and buy their wives expensive gowns and carriages. Artisans—tailors, carpenters and other skilled workmen—also prospered, as did shop owners who dealt in a variety of goods. Benjamin Franklin credited his shrewd wife, Deborah, with laying the foundation of their wealth with her tradeswoman's skills.

Several hundred miles inland was the "back country," and at the time of the Revolution, not many people went there by choice. Most were poor and landless—younger sons, for example, whose older brothers had inherited the family's property. Life on the outskirts of civilization was hard and often violent. Morals on the Western frontier were often much more relaxed than they were in the civilized East.

The Blue Anchor Inn, Philadelphia, Pa., 1776 Bettman/Corbis

America in 1776 was also a diverse nation. The first census, taken in 1790, revealed that only about 60% of the people came from England. The rest were German, Irish, Dutch, Scottish, Swedish and African.

Men wore clothes that were as colorful as the ladies' garb. One male fashion plate in New York ordered a suit of "superfine scarlet plush and a vest of light blue plush." Among the ladies, the beauty business was already a major force in the economy. "Fashion dolls" wearing the latest styles circulated through the city and the country. Women regularly spent a half day getting their hair "permanented" for a ball. Ladies seeking to preserve the sheen of youth spent a fortune on "paints" from China and lip salves from India.

Molly Tilghman of Chestertown, Md., summed up the prevailing opinion when she told her cousin Polly Pearce: "Wisdom says beauty is a fading flower but it attracts more admiration than wit, goodness or anything else in this world."

Another American tradition beginning to take root was female independence. The wife of Sueton Grant ran her husband's shipping business in Newport, R.I., for more than 30 years after his death in 1744. As a teenager, Eliza Lucas began experimenting with various plants on her father's Wappoo Creek Plantation, near Charleston, S.C. Soon she was raising indigo, which became one of the most profitable crops in the South.

Philadelphia's Lydia Darragh, America's first female undertaker, operated her business for almost a decade before the Revolutionary War began. During the war she was one of George Washington's most successful spies.

"Domestic felicity" was considered vital to everyone's peace of mind, and although divorce was legal, it was also rare. Although money played a part in marriages among the more affluent, family life was often full of affection. The love letters Col. Thomas Jones of Virginia wrote to his wife began "My Dearest Life."

Not everyone achieved this level of bliss. One notoriously unhappy marriage involved Col. John Custis of Arlington, Va., and his wife, Frances Parke. According to local accounts, they would go for weeks without speaking. One day, on a carriage ride, Mrs. Custis realized he was driving their "equipage" straight into Chesapeake Bay.

"Where are you going, Mr. Custis?" she asked. "To hell, Madam," the colonel replied. "Drive on," she said. "Any place is better than Arlington."

The colonel—or his horses—apparently changed their minds.

By 1776, the Atlantic Ocean had become what one historian has called "an information highway" across which poured books, magazines, newspapers and copies of the debates in Parliament. The latter were read by John Adams, George Washington, Robert Morris and other politically minded men. They concluded that the British were planning to tax the Americans into the kind of humiliation that Great Britain had inflicted on Ireland.

As eight years of war engulfed the continent, not a few of the rebels saw that the Revolution was a spiritual enterprise that would never really end. Dr. Benjamin Rush, a Pennsylvanian who signed the Declaration of Independence, wrote that the war was only the first step in the Revolution's destiny to transform America and the world.

History confirmed his intuition. In the next hundred years, other nations and peoples would issue 200 similar declarations.

Mr. Fleming is a former president of the Society of American Historians. This article was adapted from his e-book, "What America Was Really Like in 1776," recently published by New Word City.