About the Data

Overview. The data accessible through the "Tracking Immigration and Customs Enforcement Detainers" data tool were obtained from Immigration and Customs Enforcement (ICE) using the Freedom of Information Act after successful court litigation by the Transactional Records Access Clearinghouse (TRAC) at Syracuse University. The data contain individual records on each recorded I-247 detainer or notice request prepared by ICE. For each detainer, information on the law enforcement agency sent the request as well as the on the individual who was the subject of the request was included in the data. In addition to demographic information, detailed criminal histories for each individual were provided. Findings reported are based on TRAC's detailed analysis of these case-by-case ICE records.

Coverage. The ICE data cover each recorded I-247 form prepared by ICE from the start of FY 2003 through the most recent date available. Updated data are requested each month from ICE through a new FOIA request submitted by TRAC. Data in the tool are then updated as soon as ICE releases the information in response to these requests. The most recently available coverage date is recorded at the top of the data tool.

Using the Data Tool: Dimensions and Definitions

Filtering the data using the three data tables. Select a different factor or dimension to display in each of the three tables. The tables are inter-connected so that the data filter from left to right. After selecting a factor to display in the left most table, select a particular row category to drill in on by clicking on that row's label in the left-most table. The middle table will then display the details for that particular selection from the left table on the dimension you had chosen to display for the middle table. In other words, if you click on a category in the left table it displays only cases within that class in the middle table. Click on a category in the middle table to display only cases within that selection in the right table. To help you keep track, your selection is displayed at the top of the table to the right.

Sorting the tabular data displayed. By clicking on the column headings in a table, you can sort the tabular data displayed. Clicking on the table column heading for the name of the dimension, sorts each tabular row in alphabetical order. Clicking a second time, sorts in reverse alphabetical order. Clicking on the column heading "Total" reverses the default sort order of largest to smallest to display from the smallest to the largest value.

Selecting what is displayed in the time series graph. The data in the graph updates to reflect the category in the table you selected when clicking on its row label. The title shown above the graph indicates the selection criteria you have chosen. Mouse-over any bar in the graph to view the value being plotted.

There are also two additional controls you can use to change what the graph displays.

  • Monthly versus FY toggle. By default, the time series graph displays data for each month. To instead display bars for each fiscal year, choose the "by Fiscal Year" option to the left of the graph.

  • Number/percent toggle. By default, the number of cases is displayed in the graph. To instead display the value as a percent of the total for your current selection, choose the "Percent" option to the right of the graph. (Note: 100 percent will be displayed if the total ("All") was the category you have currently selected.)

Data dimensions. To change the set of categories displayed in a table, select a different factor or dimension from the pull-down menu above each table. The following factors can be selected:

  • Fiscal Year. This is always the fiscal year when ICE prepared the I-247 form. The federal government's fiscal year runs from October 1 to September 30. So, for example, FY 2015 will return cases filed from October 1, 2014 through September 30, 2015.

  • Month and Year. This is the calendar month and year when ICE prepared the I-247 form.

  • State. The state or territory where the law enforcement agency sent the ICE detainer hold or I-247 notice is located.

  • County-Facility Detainer Sent. The name of the specific facility along with the county in which it is located sent the ICE detainer hold or I-247 notice request. Note that ICE withheld the county information from TRAC so the county is based upon TRAC's research. Please email trac@syr.edu if you find any corrections are needed in the county assignments.

  • Facility Type. The category of detention facility—federal, state, county, or local—where ICE recorded the ICE detainer hold or I-247 notice request was sent.

  • ICE Assumed Custody After Detainer Issued. Whether ICE records booking the subject of a detainer hold or I-247 notification request into custody on or after the date the I-247 was prepared. That is, did ICE actually take custody of the individual being sought. This is based upon the recorded details of just when and where an individual is booked into ICE custody. Because of the migration in 2009 from ICE's old Deportable Alien Control System (DACS) database to its newer Enforcement Integrated Database (EID) system, ICE claims that the retrieval of custody records originally recorded in the older DACS system may be less reliable. Caution should therefore be exercised in relying upon data recorded for this earlier period.

  • Notice (Not Detainer) Issued. The particular type of ICE I-247 form ICE used. An I-247 "notice" form only asks that the law enforcement agency notify ICE of a pending release during the time the individual is otherwise in custody, and does not request that the person be detained beyond the point at which he or she would otherwise be released.

  • Detainer Refused. ICE recorded that the law enforcement agency refused to comply with the ICE I-247 request. TRAC notes that the field ICE uses to track law enforcement agency refusals is not a required field in ICE's database. Rather, entry of information is optional. The field is used to record a variety of different reasons why ICE "lifted"—that is withdrew—a custody transfer request. These recorded "lift" reasons often disagree with other information ICE records on whether the individual was actually booked into its custody. For example, ICE sometimes records an agency refused its transfer request even though ICE records it actually assumed custody of the individual. Therefore great caution should be exercised when using this information as it may not be reliably recorded by ICE.

  • Most Serious Criminal Conviction (MSCC). The recorded most serious offense the individual was convicted for. Offense categories utilize the National Crime Information Center (NCIC) coding system maintained by the Federal Bureau of Investigation. Where there are multiple convictions, ICE identified the most serious offense.

  • Seriousness Level of MSCC Conviction. ICE classifies National Crime Information Center (NCIC) offense codes into three seriousness levels. The most serious (Level 1) covers what ICE considers to be "aggravated felonies." Level 2 offenses cover other felonies, while Level 3 offenses are misdemeanors, including petty and other minor violations of the law. TRAC uses ICE's "business rules" to group recorded NCIC offense codes into these three seriousness levels.

  • Criminal History. Whether the individual had ever been charged or convicted of any crime, including minor violations of the law punishable only by a fine. The category "charged" is recorded when the only charge recorded is either still pending, when the individual was found not guilty, or the charge was dismissed. TRAC uses ICE's recorded charge-by-charge, conviction-by-conviction, criminal histories to group each individual into the appropriate category.

  • Age Group. The recorded age of the individual at the time the I-247 form was prepared by ICE.

  • Citizenship. The recorded citizenship of the individual.

  • Gender. The recorded gender of the individual.

TRAC Reports on ICE Detainers

For a listing of TRAC reports on other immigration enforcement topics, go here.

Additional TRAC Immigration Enforcement Data and Tools

To access additional data using other TRAC immigration enforcement tools, go to this directory of data tools.