Darıca is a municipality and district in Kocaeli Province, Turkey. It lies in the northwestern part of the country, on the Gulf of İzmit, and covers an area of 23 square kilometres. Its population was recorded as 225,602 in 2022, making it one of the more densely settled districts of the province.
The town was previously known as Aretsou (Αρετσού) among its native Greek population, a name that reflects the area's earlier demographic history before the population exchanges of the early twentieth century.
Darıca is administered by a mayor; as of the source material, the office was held by Muzaffer Bıyık. The district's small land area combined with its large population gives it a distinctly urban character within the wider Kocaeli region.