How many illegal immigrants came into the US during obamas 2 terms?
Executive summary
The best available estimates put the number of people who joined the U.S. unauthorized population during Barack Obama’s two terms in the low millions, but the exact figure depends on the data source and whether one counts entries, net population change, visa overstays, or border returns; academic and government sources cluster around roughly 1.5–1.7 million for 2009–2013 while advocacy analysts who extend the window to 2015 calculate as many as 2.5 million arrivals since 2009 [1] [2]. Data limitations — differing definitions of “joined,” inclusion or exclusion of visa overstays, and the gap between “apprehensions” and unique entrants — mean any single headline number will simplify complex measurement choices [1] [2].
1. What researchers actually measure versus what the question asks
Studies cited by analysts estimate changes in the unauthorized population — not a direct count of unique border crossers — and so reports that "X people joined the illegal population" combine entries, visa overstays and statistical inferences from survey and census data rather than a ledger of individual crossings [1]. For example, Pew’s and the Center for Migration Studies’ estimates of roughly 1.5–1.7 million people “joining” the undocumented population from 2009 to mid‑2013 are derived from demographic analysis of survey and census patterns, with Pew noting caveats about arrival-window definitions that affect the totals [1]. The Center for Immigration Studies’ higher 2.5 million figure adds an additional 790,000 for mid‑2013 to May 2015, illustrating how extending the window or changing methodology raises the count [1].
2. What the major estimates say and why they differ
Nonpartisan academic centers—Pew Research Center and the Center for Migration Studies—produce lower tallies: Pew’s methodology implies about 1.5 million and CMS about 1.7 million people arrived during the early Obama years up to 2013, with Pew explicitly warning that “less than five years” arrival buckets can include 2008 arrivals that distort the 2009–2013 slice [1]. By contrast, the Center for Immigration Studies (CIS), an immigration‑restriction advocacy group, combined CMS/Pew‑period estimates with additional census analysis through 2015 to claim roughly 2.5 million joined the illegal population since 2009; that higher number reflects both a longer measurement window and CIS’s interpretation of Census Bureau data [1]. The methodological differences — arrival window, inclusion of overstays, treatment of return migration, and source datasets — explain most of the divergence.
3. Why enforcement and apprehension figures don’t answer the question
Border apprehensions and deportation totals are often used as crude stand‑ins for inflows, but they are not the same as unique new arrivals: apprehensions count encounters and can include multiple apprehensions of the same person, and removals measure outbound enforcement actions rather than inbound flows [2] [3]. For context, the highest combined apprehension year early in Obama’s presidency reached 889,212 encounters in 2009, but policymakers and analysts caution that apprehensions are an imperfect proxy for unique entries [2]. Likewise, the Obama administration recorded millions of removals (DHS and other analysts cite roughly 2.7–3.0 million formal removals during 2009–2016), which speaks to enforcement intensity not net arrivals [4] [5] [6].
4. How to interpret a single number and what’s missing
Reporting a single definitive number for “how many illegal immigrants came into the U.S. during Obama’s two terms” masks choices: whether to count only new long‑term residents, to include short stays, to include visa overstays, and how to treat return migration and repeat crossings [1] [2]. Independent researchers offer a defensible range: roughly 1.5–1.7 million based on Pew and CMS through 2013, and up to about 2.5 million if one accepts CIS’s additional 2013–2015 calculation; other metrics (apprehensions, removals) are related but answer different questions about enforcement and encounters [1] [2] [4].
5. Bottom line and caveats for readers
The most cautious, research‑center‑based answer is that about 1.5–1.7 million people appear to have joined the unauthorized population in the primary 2009–2013 window, while a policy‑oriented reinterpretation that extends the period and uses alternate census touches puts the figure closer to 2.5 million since 2009; neither approach produces a precise headcount of unique illegal crossings because of methodological limits and differing agendas among sources [1] [2]. Where possible, focus on the definitions behind each number: the choice of timeframe, inclusion of overstays, and whether the figure is an arrival estimate or an enforcement count determines what the statistic actually says [1] [2] [4].