Otoyol 1

O-1 shield}}
O-1
The First Beltway
1. Çevreyolu
Route information
Length24 km (15 mi)
Existed1973–present
Major junctions
West end D.100, O-3 in Eyüp, Istanbul
East endBağdat Ave. in Kadıköy, Istanbul
Location
CountryTurkey
RegionsMarmara
ProvincesIstanbul Province
Major citiesIstanbul
Highway system
  O-2

Otoyol 1 (English: Motorway 1), abbreviated as O-1 and locally referred to as The First Beltway (Turkish: 1. Çevreyolu), is a controlled access highway in Istanbul, Turkey. The O-1 serves as the inner beltway and is one of three intercontinental motorways in the city, the others being the O-2, and O-7, as well as connecting the European and Asian parts of the city via the Bosphorus Bridge.

It starts Osmaniye neighborhood in Bakırköy district on the European part, runs through the city over the Golden Horn and the Bosphorus, and terminates in Söğütlüçeşme neighborhood of Kadıköy district on the Asian part. Otoyol 1 is toll-free, however the Bosporus Bridge is a toll bridge in both directions, having its toll plaza at the Asian side. The O-1 is connected via three feeder highways to The Second Beltway.

O1 Haliç Bridge Halıcıoğlu entrance
O1 Haliç Bridge Ayvansaray entrance