Abstract Context Primary hyperparathyroidism (PHPT) increases the risk of bone loss, debilitating fractures, kidney stones, impaired renal function, and neurocognitive symptoms. Studies describing the natural history of PHPT have been limited to small samples, single-institutions, or specific populations. Objective We assessed the natural history of PHPT through a large, diverse national cohort from an electronic health record (EHR) dataset representing over 100 million patients. Methods The TriNetX database was queried for adult patients with PHPT. We extracted demographics, comorbidities, and longitudinal biochemistries. Primary outcomes included major osteoporotic fracture (MOF) and chronic kidney disease (CKD). Outcomes were stratified by treatment strategy (surgical parathyroidectomy (PTX) vs non-surgical) and age. Results Among 49,119 patients with PHPT, 23.6% were treated surgically at a median of 2.0 years post-diagnosis. At diagnosis, median age was 72 years, 73.2% were female, and median calcium level was 10.9 mg/dL. Black and older patients underwent PTX less frequently than white and younger patients. MOF 10-year incidence was 4.5% (PTX) and 6.7% (non-surgical), with median 2.7-year delay with PTX compared to non-surgical. PTX-associated MOF absolute risk reduction (ARR) was 0.54% (age < 65) and 2.42% (age ≥ 65). CKD 10-year incidence was 22.1% (PTX) and 33.5% (non-surgical), with median 2.8-year delay with PTX. PTX-associated CKD ARR was 17.1% (age < 65) and 8.28% (age ≥ 65). Conclusions We report one of the largest, representative, population-based natural histories of PHPT with different management strategies. A minority of patients underwent PTX, especially in older age. Patients managed surgically had lower incidence of fracture and CKD, and older patients experienced differential benefit.