Registered Nurses in Ontario, CA
Browse 30 Registered Nurse providers listed in NPPES with a practice address in Ontario, California.
How Ontario compares with the U.S.
Ontario has 17 Registered Nurses per 100,000 residents, about 38% of the U.S. rate of 44.
That is 30 active Registered Nurses with a practice address in Ontario, for a population of 180,547.
The California rate is 34 per 100,000 residents.
What these numbers mean
Clinicians per 100,000 residents compares places of different sizes. We count active clinicians who list a practice address in the area in the federal NPI registry (NPPES) and divide by the number of people who live there, according to the U.S. Census Bureau. The U.S. rate is the same calculation for the whole country.
A higher number does not mean it is easier to get an appointment, that wait times are shorter, or that care is better. It also does not show how many clinicians are accepting new patients or which insurance plans they take. A lower number does not by itself mean there is a shortage.
City counts use the city name in each clinician's practice address. That postal city can cover a larger or smaller area than the city limits the Census Bureau uses for population, and many clinicians list only one address even if they work in several places.
Too few Registered Nurses in Ontario are listed in the CMS Medicare file to report Medicare assignment or telehealth shares.
These figures summarize public federal data. They do not measure quality of care, appointment availability, or whether a clinician accepts your insurance or new patients. Registry addresses can be out of date. Please confirm details directly with the office and your plan. This information is not medical advice.
Prepared by T-MedInfo from NPPES, CMS and U.S. Census Bureau data. Questions or corrections: support@true-medinfo.com ยท Methodology
Sources: Clinician counts and practice addresses: NPPES NPI Registry, Centers for Medicare & Medicaid Services (CMS), data as of August 2026. Population: U.S. Census Bureau, American Community Survey 2020-2024 5-Year Estimates, Table B01003 (Total Population).
Gerardo Albert Regalado , FNP
Registered Nurse
Ricardo Vela , NP
Registered Nurse
Mary Adetula
Registered Nurse
Florifis Almero
Registered Nurse
Kiahna Andrews
Registered Nurse
Adelaida A Zavala , RN
Registered Nurse
Irene Bacus
Registered Nurse
Kathleen Fowler Bolding , RN
Registered Nurse
Priscilla Cabreza , FNP
Registered Nurse
Taekyung Cha
Registered Nurse
Dr. Georgina Floyd , DNP, RN
Registered Nurse
Maria Teresa Del Rosario Genuino , RN
Registered Nurse
Zhicheng Guan
Registered Nurse
Gynieka Giselle Harvey , RN
Registered Nurse
Mengshan Huang
Registered Nurse
Meena Kakar , NP
Registered Nurse
Naomi Kihugu
Registered Nurse
Rosa E Loyola
Registered Nurse
Nancy Maina
Registered Nurse
Stephanie Miano , RN
Registered Nurse
Frequently Asked Questions about Registered Nurse in Ontario
Each practitioner profile shows the NUCC taxonomy code and any state license number the practitioner reported to NPPES, plus a link to the California licensing board lookup. NPPES entries are self-reported; current license status is published only by the state board.
This list shows NPI records that are active in NPPES. A deactivated NPI keeps its profile with the deactivation date and practice history; find it with the site search by name or NPI number.
Other Specialties in Ontario
Registered Nurses in Other California Cities
Cities with the most listed practitioners first.