Observation units (OUs) improve patient outcomes, decrease cost, and increase ED efficiency. Unlike adults, characteristics of OUs have not been well delineated for the pediatric population. This study characterizes pediatric OUs (POUs). Telephone/email survey sent July-December 2016 to 194 US pediatric residency programs. Sub-analysis of AHA database information also done. Survey response rate 60%(116/194). Results: median (range): ED census 53,500 (7,300-207,377), ED admissions 12% (4%-25%). 56% diverted ambulances, 77% rarely, 15% sometimes, 8% daily. 75% used midlevel providers (MLPs), 17% nurse practitioners (NPs), 12% physician assistants (PAs), 71% both. 24% (28/116) of hospitals placed pediatric patients in an OU or plan to open POU: pediatric patients only (POU) 12%, combined pediatric/adult patients OU (COU) 6%, planned POU 6%. If no POU, pediatric observation status patients were placed in ED (7%), scattered throughout inpatient floors (93%). Reasons for not having POU: lack administrative support (34%), space (32%), staff (7%), finances (3%), combination (24%). Of hospitals with POUs, median 7% (1%-10%) of ED patients placed in POU. Location: within/next to ED (71%), inpatient floor (29%). POU beds median 12 (4-27), patient to nurse ratio 4:1 (3:1-6:1). 50% used MLPs (66% NPs, 33% both). POU existed median 5 years (range 0-26 years): < 1 year (8%), 1-5 years (38%), 5-10 years (31%), 10-15 years (8%) >24 years (15%). 46% of POUs have existed <5 years. Patients cared for: ED (29%), pediatrics (21%), ED/pediatrics (43%), pediatric medical/surgical (7%). 80% used residents. Administration: ED (71%), pediatrics (29%). Top 5 conditions: respiratory distress (15%), asthma (11%), gastroenteritis (11%), appendicitis (9%), bronchiolitis (9%). Age exclusions: newborns (24%), infants (24%). 92% other exclusions: 64% psychiatric, 27% psychiatric/surgical, 9% surgical; 50% held inpatients; 92% sometimes, 8% rarely. Hospitals with POU vs no POU: ED inpatient admissions median 17% (10%-20%) vs. 10% (4%-25%) (p=0.0099*), annual ED census 47,500 (12,775-90,000) vs. 52,500 (7,300-127,000) (p=0.57, NS). 40% used MLP vs. 83% (p=0.0295*). AHA database available for 92 of 116 hospitals. 83% (69/92) hospitals provided primarily general medical care (GH): 7% (5/69) dedicated POU, 6% (4/69) COU. GH with dedicated POU vs no POU: inpatient beds median 835 (528-926) vs. 630 (268-973) (p=0.013*), annual admissions 39,804 (28,535-62,342) vs. 30,790 (16,940-47,988) (p=0.0004*). 17% (20/92) hospitals provided primarily children’s general medical/surgical services (CGH): 25% (5/20) POU. CGH with POU vs no POU: outpatient census median 515,164 (301,203-1,116,771) vs. 206,864 (133,758-447,619) (p=0.014*). Total hospital personnel median 5,025 (2,038-7,408) vs. 2,566 (1,593-4,853) (p=0.030*). Nearly 1/3 of pediatric residency program associated hospitals place pediatric patients in a dedicated OU or plan to open one.