The Ontario Line is an under-construction rapid transit line in Toronto, Ontario, Canada. Its northern terminus will be at Eglinton Avenue and Don Mills Road, at Science Centre station, where it will connect with Line 5 Eglinton. Its southern terminus will be at the existing Exhibition GO Station on the Lakeshore West line. The Ontario Line was announced by the Government of Ontario on April 10, 2019. As of November 2022, the estimated cost for the 15.6-kilometre (9.7 mi) line was CA$17 to $19 billion with an estimated completion in 2031. Originally, the cost was estimated at $10.9 billion with completion by 2027. A groundbreaking ceremony for the project took place on March 27, 2022. Upon opening, the plan is for the line to assume the "Line 3" moniker currently used by Line 3 Scarborough, which is expected to close permanently in 2023.