San Ildefonso – La Granja, with strategic resources as water, Valsaín's famous pine grove, and its recognized Monumental and Cultural Heritage is a trial of the Illustration philosophy, where Carlos III, ahead of his time,  already made "planning" the tool that allowed him to bring wisely together historical Heritage with modernity and economic growth, progress and quality of life respecting the natural environment, the model recovered after a long process of regression fruit of the dictatorship. 

The municipality count on a very powerful public sector represented by the National Heritage Institution, Ministry of Environment..., making a great part of its patrimony as  public owned and, therefore, shown in all the Planning Schemes of the Natural Resources of the Guadarrama. This, together with the shortage of building land, retail land use or industrial destination land, gives the municipality a peculiar character.

The described situation turns the City Council in the valid, and indispensable speaker, among administrations and public and private entities, and is constituted as the main economic revitalizing force; planner of the development based on endogenous resources, and intermediary on the land market with a Master Plan (PGOU), an Strategic Plan for Development, which guidelines have been agreed  among all the economic and social sectors, and an exemplary Municipal  Housing Plan, which  is developing successfully since 1996.

Consistent with this "preconceived San Ildefonso", with this illustrated "must be", the City Council, continues making the axis of its territory management the planning, the management and the commitment of all the social, public and private agents.

In this paradigm of development adopted for the municipality, it is only conceived a model of sustainable, balanced, compact and integrated urban growth. For it by means of planning, the City Council is making the most of the sustainable use of the public spaces, regulating the market of the public land, restoring architectural heritage, promoting the building of subsidized housing (VPO), with strict monitoring of the guidelines of sustainable development marked and timed annually by the needs of the local population vegetative growth and investing in the preservation of the natural and cultural environment, guaranteeing, thus, the quality of life of the neighbours, but also the constitutional right of access to housing for the new generations, with preferential treatment to disadvantaged groups like the oldest and people with some kind of disability, even being this a regional government power.