The name Cromarty variously derives from the Gaelic crom (crooked), and from bati (bay), or from àrd (height), meaning either the "crooked bay", or the "bend between the heights" (referring to the high rocks, or Sutors, which guard the entrance to the Firth), and gave the title to the earldom of Cromarty. Its name in 1264 was Crumbathyn.
The town grew around its port, formerly used by ferries, to export locally-grown hemp fibre (from cannabis), and by trawlers trawling for herrings. The port was a British naval base during WW1 and H.M.S. Natal blew up close by on 30 December 1915 with heavy loss of life. Today, the port is home to the UK's smallest vehicle ferry, running across the Firth to Nigg (home to a large facility formerly used for the manufacture and maintenance of oil rigs and an oil terminal connected to the Beatrice oilfield). It runs from June to October, from roughly 8.00 a.m. to 6.00 p.m. The vessel is called the Cromarty Rose.
Cromarty is architecturally important for its Victorian cottages in the local vernacular style. The thatched house with crow-stepped gables in Church Street, in which the geologist Hugh Miller was born, still stands, and a statue has been erected to his memory. To the east of the burgh is Cromarty House, occupying the site of the old castle of the earls of Ross. It was the birthplace of Sir Thomas Urquhart, the translator of Rabelais.
The burgh is also noted as a base for viewing the local offshore sea life. These include one of the most northerly groups of bottlenose dolphins. Cromarty along with Chanonry Point just round the coast is one of the best places in Europe to see these animals close to the shore. The University of Aberdeen department of zoology lighthouse field station is based in Cromarty.
Cromarty gives its name to one of the British Sea Areas used to provide weather forecasts to shipping.