Why do Legislative Districts vary so much in size?

According to the National Conference of State Legislatures, the number of seats in the lower house of state legislatures varies from a high of 400 in New Hampshire to a low of 40 in Alaska. But what really matters is how much population each legislator represents. The table lists the 10 states with the highest and lowest populations and the population per legislator. California has by far the largest population per district, New Hampshire the lowest.