Panama Canal: History and How It Works
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The Panama Canal is 82km of locks and channel connecting the Atlantic and the Pacific across the isthmus, and the engineering behind it is more interesting than the postcard version suggests. This is the story of how it works and how it got built; if you’re planning where to actually stand and watch it, see our guide to visiting the canal instead.
How the Locks Work
Three sets of locks did the original job when the canal opened: Gatún, on the Caribbean side, with three chambers, and Pedro Miguel and Miraflores on the Pacific side. Ships don’t get pumped uphill, the canal is gravity fed. Each lock chamber floods or drains using water gravity fed down from Gatún Lake, the artificial reservoir that sits at the canal’s summit, and ships are raised about 26 meters up to the lake’s level on one side, then lowered the same amount on the other.
The electric “mules,” the locomotives that run on rails along the lock walls, are a common point of confusion. They don’t tow the ship, the ship moves through the locks under its own engine power. The mules’ job is to stabilize and center it in the chamber so it doesn’t scrape the walls. A full ocean to ocean transit takes roughly 8 to 10 hours.
The French Failure
The first serious attempt came from Ferdinand de Lesseps, fresh off building the Suez Canal, starting in 1880 with a sea level design that assumed the isthmus would behave like the Egyptian desert. It didn’t. Yellow fever, malaria, and mudslides killed more than 22,000 workers before the French effort collapsed, one of the deadliest construction failures in modern history.
The American Build and Gorgas’s Precondition
The United States took over construction in 1904 and switched to a lock and lake design rather than repeating the sea level attempt. The real breakthrough wasn’t engineering, it was public health: Dr. William Gorgas ran a mosquito control campaign that got yellow fever and malaria under control, without which the workforce couldn’t have survived long enough to finish the job. The canal opened on 15 August 1914, with the SS Ancon making the first official transit.
The 1999 Handover
The Torrijos-Carter Treaties, signed 7 September 1977, set the terms for Panama to eventually take over the canal from the United States. Full transfer happened at noon on 31 December 1999, and the Panama Canal Authority (ACP) has run it ever since, an autonomous Panamanian agency rather than a government ministry.
The 2016 Expansion
A third lane of traffic opened on 26 June 2016: the Agua Clara Locks on the Atlantic side and the Cocolí Locks on the Pacific side, built to handle Neopanamax ships too large for the 1914 originals. The expansion roughly doubled the canal’s cargo capacity and is the reason today’s container ships passing through look considerably bigger than the ones in the old black and white construction photos.
A drought in 2023 and 2024 did cut the number of daily transits for a stretch, a real event with real shipping consequences at the time. It’s fully resolved as of 2025 and isn’t something that affects a visit to either visitor center today, it was a cargo scheduling story, not a sightseeing one.
Planning Around It
If you want to see any of this in person rather than just read about it, our visiting the canal guide covers Miraflores against Agua Clara, and our plan your canal day guide walks through tickets, timing, and what to pair it with. Most first timers fold the canal into day 2 of a 2 day Panama City itinerary ; it works just as well nested into a longer trip.
Book these before you go
For the official record on operations, capacity, and current transit statistics, the Panama Canal Authority publishes its own data, and visitcanaldepanama.com is the authoritative source for the visitor centers themselves.