Everyone is welcome to share and re-post any of these map links. There is no need to ask first. Please follow these simple rules:
1. When you post a map link, please encourage your readers to click the "Map Tips" link in the upper left corner. Many questions about the maps will be answered by those tips.
2. It is preferred that you use a map link instead of embedding a 'live' map.
3. Include in your post a credit thanking https://mappingsupport.com.
4. Do not use these map links for any commercial purpose.
In addition to state legislature district maps, a congressional district map has also been produced and can be seen at https://goo.gl/Ops2aL.
Questions, corrections, comments, etc can be emailed via this contact page or posted on the Gmap4 Facebook page.
The term "gerrymander" refers to drawing district boundaries in order to favor a certain political outcome.
Want to know who decides where voting district boundaries are drawn in your state? The Brennan Center for Justice (New York University School of Law) has complied that information here. This analysis covers both congressional districts and state legislature districts.
The Brennan Center also posts periodic updates on the status of the various lawsuits underway in several states challenging gerrymandered voting districts. Here is their late April 2017 update.
Another excellent source of information on the status of lawsuits that challenge gerrymandered voting districts is this Election Law Blog.
Log of Map Changes
August 9, 2017
The map now has improved support for state legislature map links that include a ll parameter (map center) and z parameter (zoom level). When the map opens it will be centered and zoomed according to those parameters.
Also, it is no longer possible to display both state legislature district lines along with congressional districv t lines. Instead, you cna opnly display one or the other. This is due to a fundamental change in the way that the congression district lines are displayed.
May 2, 2017
Initial map launched.
My name is Joseph Elfelt and I produced the state legislature district maps you are reading about. To be honest, I feel the work I am doing to help shed light on gerrymandering is sufficiently important that I intend to continue producing similar maps even without any financial support. But just like you, the reality is that I need to buy groceries, pay for housing and keep up with life's other bills.
To the best of my knowledge, the voting district maps I am producing are the first ones that let anyone make their own custom map link that highlights any district when the map opens.
I have also produced maps that show all of the congressional districts. To see these maps, click the basemap button on any map - it is next to the "Menu" button. Then look under the "Overlay" heading (mobile users scroll down) and click "Congress_house_districts". These congressional maps have their own Map Tips page.
If you would like to support my work you can do so through PayPal. You do not need a PayPal account to donate. All you need is a credit card.
Open Any State Legislature District Map
1. Open Gmap4
2. Click or tap the basemap button (next to the "Menu" button)
3. Look under the "Overlay" heading. Mobile users need to scroll down.
4. Select "State_legislature_districts"
You can make a Gmap4 link that will open any state legislature district map. Here is the general form for each of these map links.
The first underline is replaced with the two character abbreviation for the state and the second underline is replaced with the word "lower" or "upper". Instead of the word "lower" you can use the word "house" or "assembly". Instead of the word "upper" you can use the word "senate".
Lower chamber: Four ways to make a map link.
Upper chamber: Two ways to make a map link.
The button "Create Custom Map Link" has more information.
Basic Map Tips
The map will only open if your browser is online.
If you open the map on a desktop or laptop computer then you will see a mouse-oriented interface. If you open the map on a mobile device then you will automatically see a touch interface.
The semi-transparent colors look the best when the basemap is the google street map. If that is not the current basemap then you can click the basemap button (next to the "Menu" button) and select "Street Map Google".
If you click a district then you will see a display showing the name of the elected person(s) along with their party affiliation, homepage, mailing address and website. Also the district will be highlighted with a color showing the person's party affiliation.
To change the basemap, click the basemap button (next to the Menu button).
To search on an address, coordinates or a placename, click Menu ==> Search. A search bar will appear at the top of the screen. After the map re-centers at the thing you searched for, then click the map and the popup will show data for that congressional district.
To turn on geolocation, click Menu ==> My location. The geolocation symbol will follow you as you move.
The map has several built-in overlay layers that can be turned on/off. One of those built-in layers will show the congressional district boundaries and another layer will show state legislature district boundaries. To see the list of overlays click the basemap button and then look under the "Overlay" heading. Mobile users will need to scroll down.
An overlay layer with a number in front of it is 'on'. Click a layer name to turn it on/off. The highest numbered layer is "on top". Usually the "top" layer can be clicked and a popup will appear showing information about the thing that you clicked.
A state legislative district might be represented by one person, two people or more than two people. It depends on the state and the chamber. Here are the colors you will see on the map and what each color means. Remember that each map shows either the lower chamber or the upper chamber for a state.
Red: All seats for this chamber and this district are held by republicans.
Blue: All seats for this chamber and this district are held by democrats.
Purple: This chamber has two seats for this district. One seat is held by a republican and one seat is held by a democrat.
Gray: Everything that does not fit in the above three categories. This includes seats that are vacant, seats held by independents, non-partisan seats and districts with more tham three seats when they are not all held by the same party.
Note that if you click the basemap button (next to the 'Menu' button) and select "All white basemap" then you will see just the district boundaries on the map.
Bizarre Examples of State Legislature Districts
Each map link below will show either the house or senate districts for one state and will be zoomed in on one district that is highlighted. The fact that there are examples from so many states shows that gerrymandering is a widespread problem. There are many other state legislator districts that have shapes just as bizarre as the examples shown below.
Simply looking at a few of these weirdly shaped districts should be enough to convince anyone that something is serious wrong. Gerrymandered voting districts like these deny all voters of all parties a fair chance to chose their politicians and instead allow politicians to chose their voters.
Alabama house district 6
Arkansas house district 18
Colorado senate district 26
Connecticut house district 143
Florida house district 70
Georgia house district 57
Illinois lower district 79
Indiana senate district 26
Iowa senate district 22
Kentucky senate district 13
Louisiana senate district 6
Maryland senate district 22
Massachusetts senate district Norfolk and Plymouth
Michigan house district 94
Minnesota senate district 44
Mississippi senate district 22
Montana house district 15
New Hampshire senate district 9
New Jersey senate district 34
New Mexico senate district 39
New York senate district 50
North Carolina district 7
Ohio senate district 20
Oklahoma senate district 45
Pennsylvania house district 14
South Carolina senate district 26
South Dakota senate district 10
Tennessee senate district 31
Texas senate district 4
Virginia senate district 28
West Virginia senate district 6
Wisconsin house district 58
Create Custom Map Link
There are two ways to make a custom map link that will focus attention on a single district.
1. Display all districts for a state and highlight one district.
Add the district number to the map link. Do it like so:
2. Display just one district.
Add the word "only" and the district number. See this example:
A few states identify their legislative districts with a name instead of a number. Here are some examples for how to specify a district name. If the district name includes a space then the best practice is to replace the space with an underline character.
You can also make a custom map link that specifies the map center and zoom level that will be used when the map opens. Start by making the map look on your screen the way you want the map to look when it opens. Then click Menu ==> Link to this map. Notice that the map link that is displayed includes an ll parameter (map center) and z parameter (zoom).
Reminder: If the map link does not include an ll and z parameter then when the map opens it will automatically be centered and zoomed based on the value of the congress parameter.
If you would like to know about other parameters you can include in a map link then here is the documentation on the link parameters that Gmap4 understands.
About the Data
These maps show two kinds of data. They show the area covered by each state legislature district and if you click a district then a popup appears with information about the person(s) representing that district.
1. District boundary data
The district boundary data comes from a GIS (Geographical Information System) server operated by the Census Bureau. That server has both a generalized and detailed version of the district boundary data as of January 1, 2016. This is the most authoritative state legislature district boundary data that is available from a single source.
The generalized district boundary data is a smaller amount of data and suitable for display when the user's view is zoomed out. This generalized boundary data for each state was downloaded from the Census Bureau GIS server as a KMZ file. That KMZ file was then processed with custom code to produce (1) a new KMZ file covering the state that displays semi-transparent colored fill and (2) a separate KMZ file for each district. When you are looking at the map with semi-transparent fill and click a district, then it is the separate generalized KMZ file for that district that provides the highlight color on the district boundary.
As you zoom in closer to a neighborhood level, then the generalized district boundary data is no longer displayed. Instead, the detailed legislature district boundary data is sent from the Census Bureau GIS server directly to your screen. These detailed district lines are all light brown (lower chamber) or light green (upper chamber) and there is no colored fill. This detailed boundary data was also downloaded from the census GIS server and processed into one KMZ file per district. When you are zoomed in and looking at a map that shows the detailed boundary data and you click a district, then it is the separate detail KMZ file for that district that provides the highlight color on the district boundary.
Finally, if you are looking at a map that only displays a single district, then you are seeing the separate detailed KMZ file described in the prior paragraph.
All of these KMZ files (6,000+!) are hosted on the MappingSupport server.
2. Elected person data
When you click a district you will see a popup with data about the person(s) elected to represent that district. That data comes from https://openstates.org/. This organization has the most current freely available data on state legislators.
Note that some states elect two people from each district to the lower chamber. When you click such a district the popup will have information on both people.
The state legislature district maps are displayed by Gmap4 which is a general purpose enhanced Google map viewer developed by Joseph Elfelt. Gmap4 can be used for any non-commercial purpose.
For more information you can visit the Gmap4 homepage which has a FAQ, list of features, lots of example map links, quick start info (on the Help page) and more.
News about Gmap4 first appears on the Gmap4 Facebook page.
Questions can be emailed via the Gmap4 contact page.