Giridih district is one of the twenty-four districts of Jharkhand state, India, and Giridih is the administrative headquarters of this district. As of 2011 it is the third most populous district of Jharkhand (out of 24), after Ranchi and Dhanbad.

Giridih district was created on 6 December 1972 by carving some parts of Hazaribagh district. In 1999 part of it became Bokaro district.It is currently a part of the Red Corridor.

The district, covering an area of around 4854 km², is bounded on the north by Jamui district and Nawada district of Bihar state, on the east by the districts of Deoghar and Jamtara, on the south by Dhanbad and Bokaro, and on the west by Hazaribagh and Koderma districts.

Giridih has an average elevation of 289 metres (948 feet). Śrī Sammeta Shikharji also known as the Parasnath Hills, located in Giridih is the highest mountain peak in Jharkhand. It is a conical granite peak located 4,477 feet (1,365 metres) above the sea level.

Giridih District is geographically divided into two natural divisions, which are the central plateau and lower plateau. The central plateau touches the western portion of the district near Bagodar block. The lower plateaus have an undulating surface and an average height of 1300 feet.In the north and north-west, the lower plateaus form fairly level tablelands until they reach the ghats when they drop to about 700 feet.

Giridih is rich in mineral resources, particularly in mica and coal and has several large coal fields with one of the best qualities of metallurgical coal in India. Gawan and Tisari blocks of the district have several mica mines, and coal is found abundantly at several places throughout the district. Mica is of importance not only to Jharkhand but to India and other countries as well.

In 2006 the Indian government named Giridh one of the country’s 250 most backward districts (out of a total of 640).It is one of the 21 districts in Jharkhand currently receiving funds from the Backward Regions Grant Fund Programme (BRGF).

According to the 2011 census Giridih district has a population of 2,445,203 roughly equal to the nation of Kuwait or the US state of New Mexico.This gives it a ranking of 182nd in India (out of a total of 640).The district has a population density of 497 inhabitants per square kilometre (1,290/sq mi) . Its population growth rate over the decade 2001-2011 was 28.33%. Giridih has a sex ratio of 943 females for every 1000 males, and a literacy rate of 65.12%.Khortha, a blend of Magahi and Bengali, is the main language spoken in Giridih district. The tribal people speak Santhali.

The district has rich forest resources and have several jungles of sal trees and bamboos, and a variety of other indigenous trees. Among other common trees are bamboo, semal, Mahua, palash, kusum, kend, Asian pear and bhelwa.Parasnath hills have a number of plants having medicinal use. Leopards, bears, jackals, wild pigs, and hares are the wild animals found in certain parts of the district which have thick forests.