Sinope (Ancient Greek Σινώπη) was a daughter of the river-god Asopus and the eponym of the Black Sea city Sinope. In Apollonius of Rhodes and Valerius Flaccus she tricks Zeus — and later Apollo and the river Halys — into swearing her perpetual virginity; Corinna and Diodorus instead have Apollo carry her to the site, where she bears him Syrus.
Adapted from Wikipedia, "Sinope (mythology)" · CC BY-SA 4.0
I.Family
Usually Sinope is daughter of Asopus and Metope, sister to other city-eponym nymphs such as Aegina. A scholium makes her daughter of Ares and Parnassa, sometimes read as an Amazonising variant.
Diodorus gives her by Apollo a son Syrus, supposed eponym of the Syrians — a genealogy that conflicts with the virginity tales.
II.Mythology
Corinna and Diodorus say Apollo carried her to the shore where the city later stood. Apollonius (Argonautica 2) and Valerius Flaccus have Zeus abduct her and swear to grant her dearest wish; she asks to remain a virgin, so he must leave her. She repeats the ruse on Apollo and Halys and stays inviolate for life.
The atlas id sinope-nymph is this Asopid eponym. She is not a historical colonial founder and should not be merged with mortal women of the same city-name.