Da'ha'nu, north latitude 19 58' and east longitude 72 45', a fort and seaport, the head-quarters of the Dahanu sub-division, lies seventy-eight miles north of Bombay and about two miles west of the Dahanu Road station on the Baroda railway, with which it has lately been connected by a good road. Off shore shoal grounds, nearly dry in parts, stretch from two to six miles to the west and about thirty miles north as far as Daman. Within the outer reefs, about four miles west of the fort, small coasting craft find anchorage in three or four fathoms. The creek can be entered at high water only. [It is high water on full and change of the moon at 1 P.M. The tidal rise at springs is about 20 feet. Taylor's Sailing Directory, 371. In 1634 the mouth of the river was crossed by a Band bank, dry at low tide and with from eight to nine feet (10-12 spans) draught at high water, O Chron. de Tis. III. 198.] The 1881 census showed a population of 3525 souls, 3215 of them Hindus, 286 Musalmans, fifteen Parsis, and nine Christians. The chief class of Hindus were the Bhandaris or palm-juice tappers. The traffic at the Dahanu railway station shows an increase in passengers from 22,291 in 1873 to 37,373 in 1880, and a fall in goods from 1514 to 1156 tons. The sea trade returns for the five years ending 1878-79 show average exports worth 14,520 (Rs. 1,45,200), and imports worth 1701 (Rs. 17,010). Exports varied from 8759 (Rs. 87,590) in 1875-76 to 19,484 (Rs. 1,94,840) in 1877-78, and imports from 1286 (Rs. 12,800) in 1874-75 to 2290 (Rs. 22,900) in 1875-76.[The details are: Exports, 1874-75 17,284, 1875-76 8759, 1876-77 18,265, 1877-78 19,484, 1878-79 8809; Imports, 1874-75 1286, 1875-76 2290, 1876-77 2128, 1877-78 1377, and 1878-79 1424,] The traffic along the Bombay-Surat road and a large timber trade at Savte, six miles inland, formerly made Dahanu a more thriving and busier place than it now is.

A municipality was established in 1866 [Government Resolution 154 of 20th January 1866.] and abolished in 1878,[Government Resolution 167 of 18th January 1878.] as the funds were not large enough to carry out useful improvements. The town has the office of a mamlatdar, sub-judge, chief constable, sub-registrar, a post and sea customs office, and a school which is held in the old travellers' bungalow.

Dahanuka occurs in one of the Nasik cave inscriptions, as the name of a town and of a river on which Ushavadat the son-in-law of Nahapan (A.D. 100) made a ferry. [Trans. Sec. Or. Cong. 328, 337.] Dahanu is mentioned as passing from Gujarat to the Portuguese under the treaty of December 1533.[Da Cunha's Bassein, 137.] In 1582 the garrison was attacked by the Moghals, but defended itself successfully. [DeCouto.XI. 195.] In 1634 Dahanu is mentioned as celebrated for its image of Nossa Senhora des Augustias' which had wrought many miracles. Ten paces from the shore was a round fortress with bastions about thirty-six feet high, including an upper story. It was well supplied with ammunition, and, besides an iron gun and a bronze six-pounder, had four falcons used for throwing two-pound stone balls. The garrison consisted of a captain with two Arab horses, several Portuguese soldiers, two corporals, and thirty messengers. [The Captain was paid 21 10s. (100,000 reis) a year; the Portuguese corporals 4s. 9d. (12 larins) a month; and the common soldiers from 2s. 9d, (7 larins) to 1s. 10d, (5 larins).] There were four Portuguese and fifty native Christian families well supplied with guns, lances, and swords. [O Chron. de Tis. III. 198.] In 1670 Ogilby mentions Dahanu as a coast town. [Atlas, V. 208.] Early in the eighteenth century (1720) it is described by Hamilton as of little account for trade.[ New Account, I. 180.] In 1739 it was taken by the Marathas under Chimnaji Appa.[Grant Duffs Marathas, 240, 242.] It passed to the British in 1817 under the terms of the treaty of Poona. In 1826 it had 600 houses, seven shops and a reservoir. [Clunes' Itinerary, 13.]

The fort on the north bank of the Dahanu river at a little distance from its mouth is of cut stone and well built. In 1818 the works, which averaged about thirty feet high and ten feet thick, were in excellent order, defended by four casemated towers with ruined terraces. Most of the interior was occupied by old terraced buildings all out of repair. There was not a single habitable dwelling within the fort, and a well totally ruined yielded a scanty supply of water. The fort gateway which was very strong and in good repair was covered by a low round wall which stretched from tower to tower. In 1862 it was described as a strong fortress overgrown with brushwood and with a ruined well. [Gov. List of Civil Forts, 1862.]