LARGEST - Urban Park in the World - Golden Gate NRA
Posted by: 
DougK
N 37° 48.328 W 122° 25.684
10S E 550346 N 4184385
The Golden Gate National Recreation Area, situated on both sides of the Golden Gate, is the largest urban park in the world, and the most popular in the U.S. National Park system.
Waymark Code: WMF828
Location: California, United States
Date Posted: 09/07/2012
Views: 14
According to
Wikipedia:
An urban park, also known as a municipal park (North America) or a public park, public open space or municipal gardens (United Kingdom), is a park in cities and other incorporated places to offer recreation and green space to residents of, and visitors to, the municipality.
Golden Gate National Recreation Area, embracing 114 square miles on both sides of the Golden Gate Bridge, is the largest urban park in the world, and the most popular in the U.S. National Park system.
This claim is from the Fun California Facts website.
With regard to largest:
The many units of the GGNRA make up 114 square miles, or 72,960 acres, or 29,526 hectares.
This exceeds Phoenix, Arizona's South Mountain Park with 16,283 acres, Philadelphia's Fairmont Park collection of 63 sections with 9,200 acres, Katowice, Poland's Silesian Culture And Recreation Park with 2,000 acres, or Mexico's Chapultepec Park with 1,800 acres.
(Source)
(Source)
Wikipedia has a developing (incomplete) page of Urban Parks.
With regard to most popular (visited):
The National Parks Conservation Association website lists the top 10 most visited NPS Units. The Golden Gate NRA is listed second after the Blue Ridge Parkway (a roadway).
The National Parks Traveler website lists the top 10 most visited NPS Units in 2007. The Golden Gate NRA is listed second after the Blue Ridge Parkway.
Wikipedia also lists the ten most visited park units, agreeing with the previous two websites.