United States historical timeline

The United States began as thirteen colonies on one ocean and ended up spanning a continent and two archipelagos, and almost everything a traveller finds strange about moving around it is a residue of how that happened. The country was assembled in pieces -- bought, ceded, annexed and admitted -- and each piece kept its own law, its own street names and often its own language of place. The single most useful thing to understand is that a state line is a real legal boundary, not an administrative one: the speed limit, the sales tax, the drinking rules and the price of a park entry can all change when you cross it.

Chronology

1. 1620 Plymouth Colony is founded, the first permanent English colony in New England, settled by the passengers of the Mayflower at a site John Smith had already surveyed and named. The settlement became the town of Plymouth, and the New England pattern a visitor recognises -- a common, a meeting house, a grid of clapboard streets -- starts here.
2. 1775 The Revolutionary War begins and runs to 1783, with the Declaration of Independence adopted in 1776. It is the reason 4 July is the national holiday, and the reason the eastern seaboard is dense with battlefield parks, preserved taverns and statehouses that a visitor encounters as a continuous heritage trail from Boston to Yorktown.
3. 1787 The Constitution is signed on 17 September, creating a federal system in which the states keep their own law. This is the institution a visitor meets most often: liquor laws, speed limits, sales taxes and licence rules are state matters, and still differ sharply at every border you cross.
4. 1790 The Residence Act approves a capital district on the Potomac, taken as Washington's founding date; Congress moves in in 1800. Placing the capital on open ground rather than in Philadelphia or New York is why the monumental core is a planned composition of axes and malls, and why the District is still not a state.
5. 1803 The Louisiana Purchase nearly doubles the size of the country in one transaction. It hands the United States the Mississippi and everything west of it to the Rockies, and it is why a French-speaking colonial city sits inside a southern state and why the interior road grid runs to the horizon.
6. 1848 Gold is found at Sutter's Mill on 24 January, beginning a rush that runs to 1855 and peaks with the arrival of the "forty-niners" in 1849. It built San Francisco, populated the Pacific coast within a decade, and displaced whole indigenous nations in the process -- the reason the West has nineteenth-century cities where it might have had none.
7. 1848 The Treaty of Guadalupe Hidalgo ends the war with Mexico and transfers the territory known as the Mexican Cession. The Southwest a visitor sees -- Spanish place names, mission churches, adobe, a border culture continuous on both sides -- is that transfer still legible on the ground.
8. 1861 The Civil War runs from 12 April 1861 to 26 May 1865, between the North and a Confederacy formed by states that seceded to preserve slavery. It left an estimated 700,000 soldiers dead, making it the deadliest war in American history, and it is the most heavily memorialised event in the country: the battlefield parks, the cemeteries, and the contested monuments a visitor now finds being removed or reinterpreted are all this.
9. 1865 Reconstruction begins as the nation attempts to rebuild, bring the former Confederate states back into the United States and grant civil rights to freed slaves. Its failure is why the 1964 Act below was still necessary a century later, and why so much of the American South a visitor travels through has two histories on the same ground.
10. 1869 The first transcontinental railroad is completed at Promontory Summit in Utah, 1,911 miles built between 1863 and 1869. The line decided which places existed: a string of towns across Nebraska, Wyoming and Utah are there because the railroad put them there, and their main streets still face the tracks.
11. 1872 Yellowstone is established on 1 March as the first national park in the United States, and is widely understood to be the first in the world. It sets the template a traveller now uses everywhere: land held in public ownership, with the boundary rather than the landowner deciding access.
12. 1886 The Statue of Liberty is dedicated on 28 October, a gift to the United States from the people of France, designed by Bartholdi with a metal framework by Gustave Eiffel. It is still the country's arrival image, and the single most visited object in New York harbour.
13. 1916 The National Park Service Organic Act creates one federal agency to run those places. It is the reason the parks share a rulebook, a pass and a ranger service across all fifty states, the District of Columbia and the territories, instead of fifty separate systems.
14. 1941 Japan attacks Pearl Harbor and on 8 December the United States declares war; Germany and Italy declare war on the United States on 11 December. The war made the country a permanent global military power, and the visitor consequences are concrete -- the USS Arizona Memorial, the wartime industrial cities, and the overseas bases and airports the period left behind.
15. 1956 The Federal-Aid Highway Act funds the Interstate Highway System, proclaimed complete in 1992. It is the most consequential date on this list for how a trip actually works: outside a handful of cities with real transit, the country was rebuilt around the car, and a hire car stopped being optional.
16. 1959 Alaska is admitted as the 49th state on 3 January and Hawaii as the 50th on 21 August. The count of fifty dates from this year, and so does the practical fact that two states cannot be reached from the rest of the country without a flight.
17. 1964 The Civil Rights Act passes the House on 10 February and the Senate on 19 June after a 72-day filibuster, prohibiting racial segregation in schools and public accommodations. It is why the places where segregation was fought -- churches, lunch counters, bridges, motels -- are now marked, funded and interpreted rather than simply standing there.
18. 1971 Amtrak begins operations on 1 May, taking over intercity passenger services that the private railroads had been shedding. It is the reason a visitor can take a train at all, and also why the network is a skeleton of what the rails once carried.

What survived, and what did not

Very little American building is old by European measure, and the country has lost more of what it had than visitors expect. Wooden construction, fire and a long habit of replacing rather than repairing took most of the colonial fabric; the mid-twentieth century then cleared large parts of city centres for highways and urban renewal, which is why so many downtowns have a gap where their oldest quarter was. The Civil War of 1861 to 1865 is the great exception in the South, where ruin and poverty afterwards meant that what stood was often too expensive to replace, and therefore survived.

The counterweight arrived late. The National Historic Preservation Act, signed on 15 October 1966, created the National Register of Historic Places, the National Historic Landmarks list and the State Historic Preservation Offices, and required federal projects to account for what they would destroy. Almost every preserved main street, restored depot and saved warehouse district a traveller now walks through is downstream of that act -- which also means the oldest thing in an American city is frequently not the most interesting one, because what survived is what someone organised to save.