Sinop Fortress Prison, (Turkish: Sinop Kale Cezaevi) was a state prison situated in the inside of the Sinop Fortress in Sinop, Turkey. As one of the oldest prisons of Turkey, it was established in 1887 within the inner fortress of the centuries-old fortification located on the northwestern part of Cape Sinop. The prison was closed down in 1997 and the inmates were transferred to a modern prison newly built in Sinop.
Located direct at the coast of Black Sea on the northwest part of Cape Sinop, the Sinop Fortress was constructed initially in the 7th century BC when the city was re-founded as a Greek colony from the city of Miletus. It was extended and repaired several times in its history by Persians, Kingdom of Pontus, Romans and Byzantines. The fortress took its main form during the reign of Pontus King Mithradates Eupator in 72 BC.

The Sinop Fortress Prison was featured in various stories and poems by notable Turkish writers, who served their sentence. Refik Halit Karay, Ahmet Bedevi Kuran, Refii Cevat Ulunay, Sabahattin Ali, Kerim Korcan and Zeyyat Selimoğlu are some of them to name.

Sabahattin Ali's poem Aldırma Gönül, written 1933 in the prison and featuring the prison life, was composed in 1977 by Kerem Güney, which became nowadays very popular song by Edip Akbayram.

The prison hosted also many intellectuals, who were charged for political reasons.

Devlet II Giray, Crimean Khan (1713)
Refik Halit Karay, journalist and novelist (1913)
Mustafa Suphi, journalist and communist politician (1913)
Ahmet Bedevi Kuran, politician (1913)
Refii Cevat Ulunay, journalist (1914)
Hüseyin Hilmi, socialist politician
Burhan Felek, journalist
Osman Cemal Kaygılı, teacher and writer (1913)
Zekeriya Sertel, journalist (1925–1928)
Sabahattin Ali, writer, poet and journalist (1932)
Kerim Korcan, novelist
Osman Deniz, army officer
Nazım Hikmet, poet