Salt-making is a patient industry. Seawater is admitted to a first pond and left; as it thickens it moves to a second, then a third, each stage more concentrated than the last, until what remains is scraped into the white ridges that line the coast road. The northern shore of Rio Grande do Norte is semi-arid right up to the waterline, which is exactly the climate the process requires, and Mossoró — the state's second city — is the largest salt producer in the country. The whole state accounts for well over ninety-five per cent of Brazilian output. The coat of arms adopted back in 1909 shows a sailing boat, standing for fishing and salt, which tells you how long this has been the answer.

Rio Grande do Norte covers 52,809 square kilometres — a little over half a per cent of Brazil — and holds about 3.3 million people across 167 municipalities. Some 90.6 per cent of its territory falls inside the Polígono das Secas, the drought polygon that receives special federal attention. Most of the interior gets under 700 millimetres of rain a year, and the irregularity matters more than the total: some years bring almost nothing at all. The vegetation that copes with this is caatinga, a thorn scrub that goes grey and leafless through the dry months and turns green within days of a downpour. This is the sertão, and for generations it exported its people as reliably as the coast exported salt.

Mossoró, population 264,577 at the 2022 census, does not rely on salt alone. It is Brazil's largest onshore oil producer, drawing around 47,000 barrels a day from more than 3,500 wells scattered across scrubland that looks like it should hold nothing. Irrigation added a third industry: the Mossoró–Baraúna–Assu corridor is the country's biggest melon-growing region, shipping the great majority of its crop abroad — of roughly 254,000 tonnes produced in 2007, some 204,000 went for export. Statewide the pattern repeats. Rio Grande do Norte supplies most of Brazil's melons, grows mango and cashew at scale, and is one of only three states producing the world's entire supply of carnauba wax.

For a provincial city in a poor region, Mossoró has an unusual habit of going early. It abolished slavery on 30 September 1883, five years ahead of the national abolition of 1888 — a local decision taken while the empire was still arguing. In 1928 the schoolteacher Celina Guimarães Viana cast a ballot there, the first vote by a woman in Brazil. And on 13 June 1927 the cangaceiro Lampião brought his band against the town and was beaten off, the only defeat he suffered in his outlaw career. Two of his men did not leave: one called Colchete died in the fighting, and another, Jararaca, was wounded, captured, and afterwards killed by his captors.

Rio Grande do Norte forms the northeasternmost tip of South America, the point where the coast stops running north and starts running west. Amerigo Vespucci's expedition reached Cape São Roque in 1501 and named it for the saint whose day it was; the same voyage found a river mouth wide enough to be called the Rio Grande, and gave the future captaincy, province and state their name. The river's own name is older and better: Potengi, Tupi for river of shrimps. The Potiguar people lived here long before either name existed. French brazilwood traders worked the coast through most of the sixteenth century, the Portuguese answered with the Forte dos Reis Magos in 1598 and founded Natal the following year, and the Dutch fought for the region from 1633 until they were finally driven out in 1654.

The coast is the state's other economy. Roughly 400 kilometres of beach runs from the rainforest remnant in the south to the dunes and salt flats of the north, taking in Ponta Negra at Natal, the cliffs and coves at Pipa, the reefs at Maracajaú and the dromedary-crossed dunes at Genipabu. Offshore, 260 kilometres northeast of Natal, sits Rocas Atoll — the only atoll in the South Atlantic, protected as a biological reserve where nothing much is permitted but science. Inland, at Pirangi, stands a cashew tree that covers somewhere between 7,300 and 8,400 square metres, its branches tracing a circumference of about 500 metres. It grew that way because its limbs bend to the ground under their own weight and take root where they touch, so a single organism sprawls to the size of about seventy ordinary cashew trees. The state's most famous chapter, though, belongs to the 1940s, when Natal's airfields became the Allies' jumping-off point for Africa — and the drought-driven migrants who built them came, as usual, from the sertão.