Lothal is one of the most prominent cities of the ancient Indus valley civilization, located in the Bh?l region of the modern state of Gujar?t and dating from 3700 BCE. Discovered in 1954, Lothal was excavated from 13 February 1955 to 19 May 1960 by the Archaeological Survey of India (ASI), the official Indian government agency for the preservation of ancient monuments. Lothal's dock—the world's earliest known—connected the city to an ancient course of the Sabarmati river on the trade route between Harappan cities in Sindh and the peninsula of Saurashtra when the surrounding Kutch desert of today was a part of the Arabian Sea. It was a vital and thriving trade centre in ancient times, with its trade of beads, gems and valuable ornaments reaching the far corners of West Asia and Africa. The techniques and tools they pioneered for bead-making and in metallurgy have stood the test of time for over 4000 years.
When British India was partitioned in 1947, most Indus sites, including Mohenjo-daroand Harappa, became part of Pakistan. The Archaeological Survey of India undertook a new program of exploration, and excavation. Many sites were discovered across northwestern India. Between 1954 and 1958, more than 50 sites were excavated in the Kutch (notably Dholavira), and Saurashtra peninsulas, extending the limits of Harappan civilisation by 500 kilometres (310 miles) to the river Kim, where the Bhagatrav site accesses the valley of the rivers Narmada and Tapti. Lothal stands 670 kilometers (420 miles) from Mohenjo-daro, which is in Sindh.
The meaning of Lothal (a combination of Loth and (s) thal) in Gujarati to be "the mound of the dead" is not unusual, as the name of the city of Mohenjo-daro in Sindhi means the same. People in villages neighbouring to Lothal had known of the presence of an ancient town and human remains. As recently as 1850, boats could sail up to the mound. In 1942, timber was shipped from Broach to Saragwala via the mound. A silted creek connecting modern Bholad with Lothal and Saragwala represents the ancient flow channel of a river or creek.
Speculation suggests that owing to the comparatively small dimensions of the main city, Lothal was not a large settlement at all, and its "dock" was perhaps an irrigation tank. However, the ASI and other contemporary archaeologists assert that the city was a part of a major river system on the trade route of the ancient peoples from Sindh to Saurashtra in Gujarat. Lothal provides with the largest collection of antiquities in the archaeology of modern India. It is essentially a single culture site—the Harappan culture in all its variances is evidenced. Two sub-periods of Harappan culture are distinguished: the same period (between 2400 and 1900 BCE) is identical to the exuberant culture of Harappa and Mohenjo-daro.
After the core of the Indus civilisation had decayed in Mohenjo-daro and Harappa, Lothal seems not only to have survived but to have thrived for many years. Its constant threats - tropical storms and floods - caused immense destruction, which destabilised the culture and ultimately caused its end. Topographical analysis also shows signs that at about the time of its demise, the region suffered from aridity or weakened monsoon rainfall. Thus the cause for the abandonment of the city may have been changes in the climate as well as natural disasters, as suggested by environmental magnetic records. Lothal is based upon a mound that was a salt marsh inundated by tide. Remote sensing and topographical studies published by Indian scientists in the Journal of the Indian Geophysicists Union in 2004 revealed an ancient, meandering river adjacent to Lothal, 30 kilometres (19 miles) in length according to satellite imagery— an ancient extension of the northern river channel bed of a tributary of the Bhogavo river. Small channel widths (10–300 m or 33–984 ft) when compared to the lower reaches (1.2–1.6 km or 0.75–0.99 mi) suggest the presence of a strong tidal influence upon the city—tidal waters ingressed up to and beyond the city. Upstream elements of this river provided a suitable source of freshwater for the inhabitants.