Zarqa () is the capital of Zarqa Governorate in Jordan. Its name means "the blue (city)". It had a population of 635,160 inhabitants in 2015, and is the most populous city in Jordan after Amman. History Although the area has been inhabited since the first century CE, the city of Zarqa was only established in 1902, by Chechen immigrants who were displaced due to the wars between the Ottoman and Russian Empires. They settled along the Zarqa River. At that time a station on the Hejaz Railway was built in the new settlement. The railway station turned Zarqa into an important hub. On 10 April 1905, the Ottoman governor issued a decree that allowed the Chechen immigrants to own the land they had settled on. The population then quickly grew in size. On 18 November 1928, the new Jordanian government issued a decree to establish the first municipal council for Zarqa. After the Transjordan Frontier Force was formed in 1926, military bases were constructed in the city by the British Army, and the city later became known as the "military city". The headquarters of Jordan's Arab Legion were also located in Zarqa. The oldest Palestinian refugee camp in Jordan, known as Zarqa Camp, is located near the city. It was set up by the International Committee of the Red Cross in 1949, after the exodus of Palestinian refugees from the 1948 Arab-Israeli War. Although the camp initially consisted of tents, UNRWA eventually replaced these tents with concrete shelters. More refugees came to Zarqa after the Gulf War, when the Kuwaiti government expelled a quarter-million Palestinians, whom it suspected of supporting Saddam Hussein. More than half of those expelled went to Zarqa or the nearby city of Russeifa. During the Black September conflict in 1970, Popular Front for the Liberation of Palestine members hijacked five airplanes, and forced three to land at Dawson's Field, an airstrip in the desert near Zarqa. Zarqa is regarded today as a "marginalized" and "conservative" city, with a large Palestinian population. It is a stronghold of political Islamism, and is home to many supporters of the opposition Islamic Action Front party, which is the political wing of the Muslim Brotherhood in Jordan. The city was home to jihadist Abu Musab al-Zarqawi, the first leader of Al-Qaeda in Iraq. About one-third of Jordanians who left to fight in the Syrian Civil War, mainly for Islamist groups, are