The earliest mention of the name Alkmaar is in a 10th-century document. As the village grew into a town, it was granted city rights in 1254. The oldest part of Alkmaar lies on an ancient sand bank a couple of meters (yards) above the surrounding region; it afforded some protection from inundation during medieval times. Its vicinage consists of some of the oldest polders in existence. Older spellings include Alckmar.[1]

On June 24, 1572, after the Geuzen captured the town, five Franciscans from Alkmaar were taken to Enkhuizen and hanged, becoming the martyrs of Alkmaar.

In 1573 the city underwent a siege by Spanish forces under the leadership of Don Fadrique, son of the Duke of Alva. The citizens sent urgent messages for help to the Prince of Orange; he responded by promising to open the floodgates of the dykes and flood the region if the need arose, which despite the protestations of the peasantry, fearful for their harvest, he proceeded to do.

Some of his dispatches fell into the hands of Don Fadrique, and, with the waters beginning to rise, the Spaniards raised the siege and fled. It was a turning point in the Eighty Years War and gave rise to the expression Bij Alkmaar begint de victorie ("Victory begins at Alkmaar"). The event is still celebrated every year in Alkmaar on 8 October, the day the siege ended.

In 1799, during the French Revolutionary Wars, an Anglo-Russian expeditionary force captured the city but was ultimately defeated in the Battle of Castricum. After that battle, on 18 October 1799, the two opposing sides held the Convention of Alkmaar which met to determine the fate of the defeated Anglo-Russian force. The French victory was commemorated on the Arc de Triomphe in Paris as "Alkmaer".

The North Holland Canal, opened in 1824, was dug through Alkmaar. In 1865 and 1867 the railways between Alkmaar and Den Helder and between Alkmaar and Haarlem were built respectively.

In the second half of the 20th century, Alkmaar expanded quickly with development of new neighbourhoods. On 1 October 1972, the town of Oudorp and the southern portions of Koedijk and Sint Pancras were added to the municipality of Alkmaar.[2]