by Morgan Cullen and Karl Kurtz
State senate districts in California and Texas have larger populations than congressional districts. Texas Senate districts after the 2010 census have an average population of 811,000--more people than live in the entire states of Wyoming, Vermont, North Dakota and Alaska. For California, with its super-sized Senate districts of 931,000 people, add Delaware and South Dakota to that list of states whose population could fit into one state Senate seat.
The lower houses with the largest average population are in California (465,00) and New Jersey (219,000). New Jersey has large Assembly districts not just because of its relatively large population but also because its 80 members all serve in two-member districts that are the same size as state Senate districts (five other states--Arizona. Idaho, North and South Dakota and Washington--have a similar practice of two-member house districts).
The smallest legislative districts? Head to the 400 member New Hampshire House of Representatives where the average legislative district has a little more than 3,000 people--although that average is a bit misleading since the urban areas in the state have multi-member districts of as many as 20,000+ constituents. The smallest population state senate districts are in North Dakota where senators represent about 14,000 people each.
These are a few of the interesting tidbits that can be culled from NCSL's updated table of average district populations based on 2010 census data.
But we decided to dig a little deeper and look at how state legislative districts have changed over the last three decades in a few selected houses of representatives (click on the chart to enlarge).
Since 1980, Nevada Assembly districts have more than tripled in size from 19,000 people to 67,000. The average Florida House district has nearly doubled in population from 81,000 to 157,000 constituents over the last three decades.
On the other hand, Michigan House members, whose districts were about the same size of those of Florida representatives in 1980, represent nearly the same number of people today--about 90,000--as they did thirty years ago. North Dakota state representatives actually represent slightly fewer people today than they did in 1980--14,000 compared to 17,000. North Dakota is the only state to have lost population since 1980.
Of course, statewide population change is not the only determinant of legislative district populations. The size of each legislative chamber also matters. Since the early 1980s, the only state that made a significant change in the size of their house chambers is Rhode Island. The Ocean State reduced its membership from 100 to 75 in 2004. As a result, Rhode Island House districts (not shown on the chart) increased 75 percent in size since 1980 (from 9,500 to 14,00), even though its population increased by only 11 percent during the same period.