Plan on about 4 h 28 min of driving for the 228-mile (367 km) trip from San Nicolás de los Arroyos to Mercedes, Uruguay, before any stops. You cross from Argentina into Uruguay at about mile 209, at the Gualeguaychú–Fray Bentos bridge.
Full advisory: Argentina, Uruguay. Advisory issued: Argentina July 10, 2026; Uruguay July 28, 2026; checked October 10, 2026.
On the roads, the State Department says:
- Argentina: “Drivers in Argentina tend to be aggressive, especially in Buenos Aires, and often ignore traffic regulations.”
- Uruguay: “Illumination, pavement markings, and road surfaces for secondary roads can be poor.”
| Distance by road | 228 mi (367 km) |
|---|---|
| Time at the wheel, no stops | 4 h 28 min |
| Main roads, in order | RN9 → RN12 → RN14 → RN136 |
| Border crossing | about mile 209, Argentina → Uruguay (the Gualeguaychú–Fray Bentos bridge) |
| Regions on the route | Buenos Aires, Entre Ríos, Río Negro, Soriano |
| Fuel estimate (car at 25 mpg) | about 9.1 gal; actual use varies by vehicle and traffic |
| Stops listed below | 3 |
Border crossing: what to bring for Uruguay
The route crosses at about mile 209, at the Gualeguaychú–Fray Bentos bridge, from Entre Ríos into Río Negro. Plan on two checks on each side: immigration for your passport and customs for the car.
| Entering Uruguay (U.S. citizens) | No visa needed for visits of 90 days or less. Passport: must be valid for 6 months beyond your arrival date. |
|---|---|
| Driving in Uruguay | You can drive on your U.S. license. |
| Entering Argentina (U.S. citizens) | No visa needed for visits of 90 days or less. Passport: must be valid when you enter; leave a blank page for the entry and exit stamps. |
| Driving in Argentina | A valid U.S. license usually works; an International Driving Permit is recommended. |
| Rental car | Cross only if the rental company authorizes it in writing and gives you the papers for the border; ask before you book. |
Sources: U.S. State Department, Uruguay (updated August 13, 2026); U.S. State Department, Argentina (updated July 16, 2026). Checked October 10, 2026; rules change, so confirm before you go.
The San Nicolás de los Arroyos–Mercedes drive in a few lines
RN9 (90 mi) and RN12 (49 mi) carry about 61% of the 228 miles. The first 209 miles are in Argentina; the last 19 are in Uruguay. It runs through 4 regions: Buenos Aires, Entre Ríos, Río Negro, Soriano. None of the 3 stops below is right on the road, so plan each as a short side trip.
Road-by-road breakdown: San Nicolás de los Arroyos to Mercedes
| Road | Route miles (from–to) | Length, mi | Region |
|---|---|---|---|
| local roads | 0–4 | 4 | Buenos Aires |
| RN9 | 4–94 | 90 | Buenos Aires |
| connecting roads | 94–95 | 1 | Buenos Aires |
| RN12 | 95–144 | 49 | Buenos Aires, Entre Ríos |
| RN14 | 144–181 | 37 | Entre Ríos |
| local roads | 181–188 | 7 | Entre Ríos |
| RN136 | 188–207 | 19 | Entre Ríos |
| connecting roads | 207–209 | 2 | Entre Ríos |
| local roads | 209–228 | 19 | Río Negro, Soriano |
- Mile 115 of this route: Buenos Aires → Entre Ríos (region line)
- Mile 209 of this route: Entre Ríos → Río Negro (international border)
- Mile 226 of this route: Río Negro → Soriano (region line)
What to see on the way from San Nicolás de los Arroyos to Mercedes
- Nature and outdoors: Ciervo de los Pantanos National Park (mile 98)
- Museums and history: Gualeguaychú Cathedral (mile 187)
Ciervo de los Pantanos National Park
About 2,500 hectares of wetlands in Campana, Buenos Aires province, are protected as Ciervo de los Pantanos National Park. It's a Ramsar Site and home to the marsh deer and plenty of waterbirds.
Gualeguaychú Cathedral
St. Joseph's Cathedral, also called Gualeguaychú Cathedral, serves as the cathedral church of the Roman Catholic Diocese of Gualeguaychú in Argentina.
Frigorífico Anglo del Uruguay
Liebig exported meat extract and corned beef from this spot on the Uruguay River at Fray Bentos starting in 1865. In 1924, the Anglo plant began shipping frozen meat from the same site.
Once you reach Mercedes
Cathedral of Mercedes
Dedicated to Our Lady of Mercy, this cathedral is the main Catholic church of Mercedes, Uruguay, and has been the seat of the Diocese of Mercedes since 1960.
Calera Real del Dacá
On the eastern edge of Mercedes beside the Dacá stream, the ruins of the Calera Real lime works date to 1722 and are considered the region's first industrial site; recent works added visitor circuits, lighting and interpretive signs.
Alejandro Berro Paleontology Museum
In a 19th-century building in Mercedes' Parque Castillo Mauá, this paleontology museum opened in 1946 around the collection of naturalist Alejandro Berro; a well-preserved glyptodon shell found on a nearby riverbank is a highlight.
More drives to Mercedes
- Salto to Mercedes, Uruguay
- Rivera to Mercedes, Uruguay
- Artigas to Mercedes, Uruguay
- Montevideo to Mercedes, Uruguay
- Melo to Mercedes, Uruguay
- Buenos Aires to Mercedes, Uruguay
More drives from San Nicolás de los Arroyos
- San Nicolás de los Arroyos to Tigre
- San Nicolás de los Arroyos to Adrogué
- San Nicolás de los Arroyos to Berisso
- San Nicolás de los Arroyos to Magdalena
- San Nicolás de los Arroyos to Chascomús
- San Nicolás de los Arroyos to Cariló
Continue Your Adventure
Frequently asked questions
How long does it take to drive from San Nicolás de los Arroyos to Mercedes, Uruguay?
About 4 h 28 min of driving without stops, over 228 miles.
How far is Mercedes, Uruguay from San Nicolás de los Arroyos by car?
About 228 miles (367 km) on the Wayro route. Other map services may show a few miles more or less, depending on where they start and end in each city.
Where does the San Nicolás de los Arroyos to Mercedes drive cross the border?
At about mile 209, from Argentina into Uruguay, at the Gualeguaychú–Fray Bentos bridge.
What do U.S. citizens need to drive from San Nicolás de los Arroyos into Uruguay?
No visa needed for visits of 90 days or less. Passport: must be valid for 6 months beyond your arrival date. You can drive on your U.S. license. (U.S. State Department, updated August 13, 2026.)
What does the U.S. travel advisory say about the San Nicolás de los Arroyos to Mercedes drive?
The U.S. State Department rates Argentina Level 1: Exercise Normal Precautions; Uruguay Level 2: Exercise Increased Caution. Read the full advisory before you go.
Which highways go from San Nicolás de los Arroyos to Mercedes?
In order: RN9, RN12, RN14 and RN136. The road-by-road table above shows the route miles for each one.
Where can you stop on the way from San Nicolás de los Arroyos to Mercedes?
Closest to the road: Ciervo de los Pantanos National Park (national park, mile 98, 12 mi from the route); Gualeguaychú Cathedral (cathedral, mile 187, 1 mi from the route); Frigorífico Anglo del Uruguay (industrial heritage site, mile 209, 5 mi from the route). All stops are described above.
How we put this guide together
Wayro calculates the route from OpenStreetMap road data; mile numbers are positions along this route, not highway markers, and "from the route" distances are straight-line, so the real detour depends on access roads. Stops are chosen from parks, natural sites, museums, historic sites and attractions close to the route: at least one strong stop for each stretch of the drive, then the best-known places nearest the road, up to nine in all. Places that are closed, private or not open to visitors are removed. Place descriptions are written by the Wayro team from official park, museum, tourism and government websites and other published sources. Safety levels and entry rules were checked against the U.S. Department of State on October 10, 2026. Conditions change, so check the linked sources before you travel.
Route data © OpenStreetMap contributors.