Clinical Trials by State: Where Medical Research Happens in the US
The geographic distribution of US clinical trials — why some states have more trials, which conditions dominate by region, and how location affects patient access to research.
The Geography of Clinical Research
State-Level Concentration Patterns
Clinical trial activity in the United States is concentrated in states with major academic medical centers, pharmaceutical industry presence, and large diverse populations. The top five states by trial count — California, New York, Texas, Florida, and Pennsylvania — account for a substantial share of all US-based clinical research. This concentration has important implications for patient access to experimental treatments.
However, the picture is more nuanced than simple state rankings suggest. Multi-site trials (which constitute the majority of industry-sponsored Phase 3 studies) spread enrollment across many states. A cancer trial headquartered at Memorial Sloan Kettering in New York may recruit participants at community oncology practices in Alabama, Nebraska, and Oregon. The geographic footprint of recruiting sites is often broader than the primary sponsor's location suggests.
Why Trial Distribution Matters
Equity and Access Barriers
Access to clinical trials can be a matter of life and death for patients with serious conditions who have exhausted approved treatment options. Geographic barriers — distance from a trial site, lack of transportation, inability to travel frequently — disproportionately affect rural patients, elderly patients, and patients with lower incomes. The uneven distribution of clinical trials raises equity concerns about who benefits from medical research and who can participate.
Major Research Hubs
- Boston/Cambridge, MA: One of the world's densest concentrations of biotech companies, academic hospitals (Mass General, Dana-Farber, Brigham and Women's), and research universities (Harvard, MIT)
- New York City: Memorial Sloan Kettering, NYU Langone, Columbia, Weill Cornell — especially strong in oncology and rare diseases
- Houston, TX: MD Anderson Cancer Center and the Texas Medical Center, the world's largest medical complex
- Research Triangle, NC: Duke University, UNC Chapel Hill, and a dense cluster of pharmaceutical and biotech firms
- San Francisco Bay Area, CA: UCSF, Stanford, and Silicon Valley biotech companies pioneering gene therapy and digital health
- Bethesda, MD: The NIH Clinical Center — the nation's largest hospital dedicated entirely to clinical research
Rural Access Challenges
Distance as a Participation Barrier
The concentration of clinical trials in urban academic medical centers creates a significant access gap for rural patients. According to published research, patients living more than 60 miles from a trial site are substantially less likely to participate in clinical research. This distance barrier affects cancer patients particularly severely, as cancer trials often require frequent in-person visits for treatment administration, blood draws, and imaging studies.
Several initiatives are working to address this gap. Decentralized clinical trials (DCTs) allow some or all trial activities to be conducted remotely — using telehealth visits, home nursing, and local laboratory facilities. The COVID-19 pandemic accelerated adoption of decentralized trial elements, and many sponsors have incorporated hybrid models (combining in-person and remote visits) into their post-pandemic trial designs. Community oncology practices and rural hospitals are also increasingly participating as satellite sites for multi-center trials, bringing research opportunities closer to where patients live.
Finding Trials Near You
Using State-Level Search Tools
PlainTrial's state profiles show all clinical trials with recruiting locations in each state, organized by condition, phase, and recruitment status. This is useful for patients looking for nearby trial sites. Key strategies for finding accessible trials:
- Search by your specific condition and state on PlainTrial or ClinicalTrials.gov
- Ask your oncologist or specialist — they often know about trials recruiting in the region
- Check academic medical centers within driving distance — many have trial matching services
- Consider trials with decentralized or hybrid designs that allow some visits to be conducted remotely
- Some sponsors provide travel assistance for participants willing to travel to trial sites
Frequently Asked Questions
Which states have the most clinical trials?
California, New York, Texas, Florida, and Pennsylvania consistently lead in total clinical trial activity. This reflects their large populations, concentration of academic medical centers, presence of pharmaceutical company headquarters and research facilities, and large patient populations across disease areas. However, trials are conducted in every state — clinical research is a national enterprise.
Does living in a state with fewer trials limit my options?
Not necessarily. Many trials are multi-site studies conducted across dozens of states. Even if a trial's primary site is in California, it may have recruiting locations in 30+ states. Use the location search on ClinicalTrials.gov or PlainTrial to find trials near you. Some trials also include remote participation options or travel support for participants.
Why do some conditions have more trials in certain states?
Geographic concentration of trials often reflects the location of major research centers specializing in that condition. The MD Anderson Cancer Center in Texas concentrates oncology trials in Houston. The NIH Clinical Center in Bethesda, Maryland attracts trials in rare diseases. Academic medical center specializations, disease prevalence patterns, and pharmaceutical company facility locations all influence the geographic distribution of trials.