The advent of modernity in Iran weakened many structures and practices, including social hangouts in cities; therefore, the public was cynical about this space. While hangouts, as a third-place and public space in a city, promote social capital, vibrant centers, and citizenship education, Tehran Daneshjoo Park, as a public space with an urban scale and physical and social features, can also be considered a hangout for various social groups. The present study seeks to identify hangouts and factors affecting their formation, continuity, or fading in this space. Accordingly, documentaries were investigated via a descriptive-survey method. Then, interviews with space users at different times and with observation instruments such as photography and behavioral mapping were employed. The results showed a hangout for artists and art lovers, vendors, and food vendors, students and young women, people with sexual identity disorders, addicts and drug dealers, and the elderly. Also, functional components such as geographical location, urban theater building, and its architectural type, platforms and stair space structure, water pool, urban furniture, enclosure in space, social components such as the presence of social observers, drug distribution, and street peddler are effective in creating and the continuation of these hangouts. Most of these hangouts are formed as part of open space with a trans-regional scale.