Over the years the point of approach from Çanakkale has moved, in all cases Kilit Bahir is to the left (west) side. I read on a site there are plans to connect the two sides by a bridge, in my mind that would be comprehensible, but also would ruin the countryside.
From the Wikipedia: Kilitbahir Castle, is a fort on the Dardanelles on the opposite side of the city of Çanakkale. It was made by Fatih Sultan Mehmet in the year 1462. It was built in 120 days by 5,000 workers that came from Romania. It was built in order to control the Dardanelles and to receive tax from the ships that pass by." Kilit means "lock" or "key", bahir seems to be "sea". So "lock on the sea". The small village surrounding the castle has taken its name.