The Second Continental Congress declared the independence of the thirteen mainland colonies south of Canada, which is the origin of the holiday. (The first Continental Congress had been convened during the Stamp Act crisis of of 1765.) The text of the Declaration had been submitted and approved by a quorum on July 2, 1776, but other members present in Philadelphia wanted to read it first. It was officially released to the public on July 4, 1776. The shooting had actually started in April, 1775, on the commons at Lexington, Massachusetts. The English had sent out a column of about 1200 men under the nominal command of Lord So-and-so (don't remember, and can't be arsed to look it up), but under the actual command of Major Pitcairn of the Royal Marines. They were marcing to Concord, Massachusetts to arrest Samuel Adams (a failed malster and rabble-rouser, celebrated today as a master brewer, which he never was, and a patriot) and John Hancock, as well as to seize the militia's store of black powder. They got into a full-fledged fire fight with several hundred militia there, and then the march back turned into a nightmare, as around three to five thousand militiamen came pouring into the area, and took potshots at the redcoats from behind trees and stone fences. Eventually, nearly every soldier and Marine in Boston was turned out to escort the battered column into town.
The city of Boston was laid under a siege, but the command was pathetic, and at any time, the English probably could have attacked and driven off their tormentors. But all they knew was that there were more than ten thousand militiamen out there, who were equipped exactly as their soldiers were--they also lacked resolve and instructions from Lord North's government. In June, the commanders of the militia came to a sort of an agreement, and decided to fortify Bunker's Hill on the Charles Town penninsula, which would have brought the English fleet under the guns of the militia. There were a couple of problems with that, however. The command was divided, and many militiamen milled around and took no part in the battle. The second was that the most active officer on the scene, Colonel Prescott, lead his men up Breed's Hill, the wrong hill, a lower elevation, and one close enough for the fleet to shell it.
The English sent out a force of about 2,000 men to land near the Charles Town neck, and take the field fortification which Prescott's men had built overnight in flank. Colonels Glover of Massachusetts and Stark of New Hampshire, however, met them at the landing place, and although driven off, convinced Clinton that it was too dangerous, so, with an arrogant contempt for the Americans, he decided on a frontal assault of Breed's Hill. Major Pitcairn led a "flying column" of men up the mud flats of the Mystic River, but was met there by Stark and Glover, and was mortally wounded. His Marines and the light infantry from Clinton's regiments were driven off in confusion.
Clinton sent his men straight up Breed's Hill. The grass in the pastures was chest high on his men, and they didn't see the stone walls which broke up the ground everywhere. This broke up their lines, and they were damned good targets as the climbed over the walls. Prescott had advised his men to shoot the officers, and said they could be found out by their fancy clothing. The casualties among musicians, sergeants and color guards was therefore very high.
Three times Clinton sent his men up the hill, and the first two times, Prescott's men sent them reeling back. Reinforcements were landed, and the third assault was made with the bayonet. Prescott's men were running out of ammunition, and had begun to fire nails, stones, bits of broken bottles, anything they could ram down their muskets. This resulted in "atrocity" stories being circulated in Europe by the English. Finally, Prescott's men were driven out, and Prescott killed. About five to seven thousand militiamen were never involved, and stayed on Bunker Hill, but Clinton wisely decided they had done enough for one day. The English suffered one third casualties, an appalling rate. They never tried anything like that again.
George Washington, who had commanded the Virginia Militia in the French and Indiand War in the 1750's had been appointed commander of the army, and he arrived after Bunker Hill. A Boston bookseller, Henry Knox, who had avidly read about war, and dreamed of being a soldier, performed a near miracle, dragging heavy artillery form upstate New York to Boston. Washington wanted to attack the city, and held a council of war in December, 1775. The old saying is that councils of war never fight--this one didn't want to, and Washington never held another council of war. In March, 1776, he sent his men up Dorchester Heights south of Boston, on a frozen, stormy night, and they erected gun emplacements without the English being aware. In the morning, the English looked out, saw the telling array of guns, and marched their men down to the docks. The next day, the fleet weighed anchor, and the English sailed off to Halifax, Nova Scotia (in present-day Canada).
This put some backbone into Congress, and they appointed a committee, which wrote the declaration. Although largely the work of Thomas Jefferson between June 11th and 28th, 1776--he borrowed heavily from authors of the Englightenment and earlier political philosophers--it was heavily edited before it was released. Washington's little army had moved to New York by this point, and he had the Declaration read out on July 9, 1776.
The Decaration of Independence
When in the Course of human events, it becomes necessary for one people to dissolve the political bands which have connected them with another, and to assume among the powers of the earth, the separate and equal station to which the Laws of Nature and of Nature's God entitle them, a decent respect to the opinions of mankind requires that they should declare the causes which impel them to the separation.
We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.--That to secure these rights, Governments are instituted among Men, deriving their just powers from the consent of the governed, --That whenever any Form of Government becomes destructive of these ends, it is the Right of the People to alter or to abolish it, and to institute new Government, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their Safety and Happiness. Prudence, indeed, will dictate that Governments long established should not be changed for light and transient causes; and accordingly all experience hath shewn, that mankind are more disposed to suffer, while evils are sufferable, than to right themselves by abolishing the forms to which they are accustomed. But when a long train of abuses and usurpations, pursuing invariably the same Object evinces a design to reduce them under absolute Despotism, it is their right, it is their duty, to throw off such Government, and to provide new Guards for their future security.--Such has been the patient sufferance of these Colonies; and such is now the necessity which constrains them to alter their former Systems of Government. The history of the present King of Great Britain is a history of repeated injuries and usurpations, all having in direct object the establishment of an absolute Tyranny over these States. To prove this, let Facts be submitted to a candid world.
He has refused his Assent to Laws, the most wholesome and necessary for the public good.
He has forbidden his Governors to pass Laws of immediate and pressing importance, unless suspended in their operation till his Assent should be obtained; and when so suspended, he has utterly neglected to attend to them.
He has refused to pass other Laws for the accommodation of large districts of people, unless those people would relinquish the right of Representation in the Legislature, a right inestimable to them and formidable to tyrants only.
He has called together legislative bodies at places unusual, uncomfortable, and distant from the depository of their public Records, for the sole purpose of fatiguing them into compliance with his measures.
He has dissolved Representative Houses repeatedly, for opposing with manly firmness his invasions on the rights of the people.
He has refused for a long time, after such dissolutions, to cause others to be elected; whereby the Legislative powers, incapable of Annihilation, have returned to the People at large for their exercise; the State remaining in the mean time exposed to all the dangers of invasion from without, and convulsions within.
He has endeavoured to prevent the population of these States; for that purpose obstructing the Laws for Naturalization of Foreigners; refusing to pass others to encourage their migrations hither, and raising the conditions of new Appropriations of Lands.
He has obstructed the Administration of Justice, by refusing his Assent to Laws for establishing Judiciary powers.
He has made Judges dependent on his Will alone, for the tenure of their offices, and the amount and payment of their salaries.
He has erected a multitude of New Offices, and sent hither swarms of Officers to harrass our people, and eat out their substance.
He has kept among us, in times of peace, Standing Armies without the Consent of our legislatures.
He has affected to render the Military independent of and superior to the Civil power.
He has combined with others to subject us to a jurisdiction foreign to our constitution, and unacknowledged by our laws; giving his Assent to their Acts of pretended Legislation:
For Quartering large bodies of armed troops among us:
For protecting them, by a mock Trial, from punishment for any Murders which they should commit on the Inhabitants of these States:
For cutting off our Trade with all parts of the world:
For imposing Taxes on us without our Consent:
For depriving us in many cases, of the benefits of Trial by Jury:
For transporting us beyond Seas to be tried for pretended offences
For abolishing the free System of English Laws in a neighbouring Province, establishing therein an Arbitrary government, and enlarging its Boundaries so as to render it at once an example and fit instrument for introducing the same absolute rule into these Colonies:
For taking away our Charters, abolishing our most valuable Laws, and altering fundamentally the Forms of our Governments:
For suspending our own Legislatures, and declaring themselves invested with power to legislate for us in all cases whatsoever.
He has abdicated Government here, by declaring us out of his Protection and waging War against us.
He has plundered our seas, ravaged our Coasts, burnt our towns, and destroyed the lives of our people.
He is at this time transporting large Armies of foreign Mercenaries to compleat the works of death, desolation and tyranny, already begun with circumstances of Cruelty & perfidy scarcely paralleled in the most barbarous ages, and totally unworthy the Head of a civilized nation.
He has constrained our fellow Citizens taken Captive on the high Seas to bear Arms against their Country, to become the executioners of their friends and Brethren, or to fall themselves by their Hands.
He has excited domestic insurrections amongst us, and has endeavoured to bring on the inhabitants of our frontiers, the merciless Indian Savages, whose known rule of warfare, is an undistinguished destruction of all ages, sexes and conditions.
In every stage of these Oppressions We have Petitioned for Redress in the most humble terms: Our repeated Petitions have been answered only by repeated injury. A Prince whose character is thus marked by every act which may define a Tyrant, is unfit to be the ruler of a free people.
Nor have We been wanting in attentions to our Brittish brethren. We have warned them from time to time of attempts by their legislature to extend an unwarrantable jurisdiction over us. We have reminded them of the circumstances of our emigration and settlement here. We have appealed to their native justice and magnanimity, and we have conjured them by the ties of our common kindred to disavow these usurpations, which, would inevitably interrupt our connections and correspondence. They too have been deaf to the voice of justice and of consanguinity. We must, therefore, acquiesce in the necessity, which denounces our Separation, and hold them, as we hold the rest of mankind, Enemies in War, in Peace Friends.
We, therefore, the Representatives of the united States of America, in General Congress, Assembled, appealing to the Supreme Judge of the world for the rectitude of our intentions, do, in the Name, and by Authority of the good People of these Colonies, solemnly publish and declare, That these United Colonies are, and of Right ought to be Free and Independent States; that they are Absolved from all Allegiance to the British Crown, and that all political connection between them and the State of Great Britain, is and ought to be totally dissolved; and that as Free and Independent States, they have full Power to levy War, conclude Peace, contract Alliances, establish Commerce, and to do all other Acts and Things which Independent States may of right do. And for the support of this Declaration, with a firm reliance on the protection of divine Providence, we mutually pledge to each other our Lives, our Fortunes and our sacred Honor.