Ilulissat is the second most populous province of Greenland.
Until official Norse Greenlandic contact in the mid-1300's, Ilulissat only consisted of Inuits. The town of Kritikpok, which was established by Norse settlers with help from the Inuit around them, became one of the first places for true Greenlandic culture to arise. After many original settlements in southern Greenland grew weak with rare contact with Vinlandic and Danish merchants, the Norse Greenlandic were forced to mix with the Inuit, forming new towns and even "interbreeding". Ilulissat was once of the majorly Inuit parts of known Greenland at the time, and the new Greenlandic culture of the 1400's and 1500's mixed well with these places. More small towns were founded, and it quickly grew in size, even faster than the other regions. Many ethnic Inuit escaped up north to avoid assimilation into the new Norse-Inuit culture, and towns such as Adgomut and Issumakattigengnerk (now defunct) were founded (even though they didn't escape the much more powerful Greenlandic government for long).
The largest town in Ilulissat, however, is the city of Puigojuitok, which was founded in 1639. It served as a haven for both Inuit and Greenlandic (which was basically just Inuit by this point) culture, as well as acting as a "gate to the far north". After the official designation of Ilulissat as a province of Greenland after the breakup of Greenland-Iceland, it played a large role in the sway of politics. It was slightly less civilized than the rest of Greenland, and didn't have an official organized government in many cities. Even though Greenlandic expansion was already at the north of the main island, places like Uiritsaktok just weren't able to get up to speed with the rest of the provinces. This soon changed, however, as they eventually warmed up to the idea of a central government and were able to urbanize properly centuries later. Puigojuitok, while not being the sturdiest town in Greenland, is still the second-most populous, with 10,243 people as of 2015.