Urban forestry NGOs commenced gaining prominence in the socio-political landscape of the 20th century. Despite a dramatic increase in the number of urban forestry NGOs (50%) in recent decades, they are rarely described in the scientific literature, and they have not been investigated in any formal, systematic manner. Little is known about the origins of many of these organisations or how many formal urban forestry NGOs are presently active across the United States. Knowledge gaps persist pertaining to organisational structure, programming, and funding. To address these gaps in knowledge, this article presents findings from a survey of 81 urban forestry NGOs in the temperate forest region of the United States. We report on typical traits of urban forestry NGOs across five themes that include "origin", "organisational structure", "funding", "partnerships", and "programming". Nearly 80% of respondents indicated that their urban forestry NGO has helped develop, shape, or implement policy in their community (e.g. tree policies & ordinances, urban forest master plans). An overwhelming majority of NGOs (90% and 83%, respectively) indicated that both private citizens and local departments were important collaborators. A vast majority of respondents (86%) indicated that their NGO routinely engages in planting trees and over 70% of urban forestry NGOs routinely participate in public events including Arbor Day celebrations and local tree giveaways. There is widespread variation regarding the size, composition, and even function of urban forestry NGOs.