Paraquat dichloride remains an important restricted-use herbicide in United States agriculture, with concerns centered on environmental persistence, ecological effects, occupational exposure, acute poisoning, and possible chronic health outcomes. This scoping review mapped United States evidence on paraquat use, environmental fate and occurrence, ecological effects, human exposure, acute poisoning, chronic health outcomes, regulation, and prevention. The review followed JBI guidance and the PRISMA extension for Scoping Reviews (PRISMA-ScR). Searches covered MEDLINE (PubMed), Embase, Scopus, Web of Science Core Collection, CAB Abstracts, AGRICOLA, ProQuest Dissertations and Theses, and selected federal and state sources for evidence published from 1964 through July 28, 2026. Searches identified 1,600 records. After 470 duplicates were removed, 1,130 records were screened and 890 were excluded. Of 240 reports sought for retrieval, 30 were not retrieved; 210 full-text reports were assessed for eligibility and 125 were excluded, leaving 85 included sources: 58 peer-reviewed studies, 20 government or regulatory reports, and 7 surveillance or monitoring reports. Paraquat use was concentrated in major agricultural regions and crops, including cotton, soybean, corn, orchards, and vegetables. Strong soil and sediment binding was reported alongside prolonged persistence and transport through runoff, erosion, spray drift, and possible volatilization. Ecological risk assessments identified concerns for birds, mammals, aquatic invertebrates, benthic organisms, and bees. Acute poisoning was the most clearly established human health outcome, with occupational incidents, accidental ingestion, severe illness, and deaths documented in surveillance data. Evidence for chronic disease was mixed; associations were reported for Parkinson disease, renal cell carcinoma, thyroid cancer, childhood leukemia, end-stage renal disease, and increased diastolic blood pressure, but exposure misclassification, correlated pesticide use, and limited biomonitoring reduced causal certainty. The evidence supports continued poisoning prevention, worker protection, exposure surveillance, environmental monitoring, and evaluation of regulatory controls. Priority research areas include air monitoring, biomonitoring, sediment assessment, prospective occupational studies, and field-based ecological research.