The PAD-US Partnership has adopted the following definition:

Protected Areas are lands dedicated to the preservation of biological diversity and to other natural, recreation and cultural uses, and managed for these purposes through legal or other effective means. (adapted from IUCN definition)

In the PAD-US, protected areas are lands held in fee ownership for permanent or very long term open space uses. These include national parks and forests, public lands generally, wildlife preserves, state and local parks and reserves, lands held by non-profit organizations and many other areas. Eventually, the PAD-US Partnership will seek to incorporate marine protected areas, as well as lands that may only be secured for shorter time frames. The PAD-US does not generally include military or tribal lands unless they are secured for open space purposes.

Easements are also considered forms of protection and separate efforts are underway to develop better inventories of these areas, coordinated with the PAD-US.

Defining the level of "protection" for any particular area usually means assessing and applying USGS Gap scores (or IUCN rankings), which indicate the degree to which any land is managed to achieve biodiversity conservation. A PAD-US Partnership report (2Mb PDF) is available describing next-generation options for such conservation measures.

The first PAD-US was published in April 2009 and is available for download.

Prior to this, there have been two major sources of national protected areas data:

• The Conservation Biology Institute's Protected Areas Database (CBI PAD) was for many years the only national level inventory of protected lands. First created in the late 1990s, the PAD was updated several times, as funding resources were available. CBI is now conducting its updates through the PAD-US and is actively involved in the PAD-US Partnership.
• The USGS Gap Analysis Program develops a wide range of conservation data and supports local conservation assessments (Gap analyses). For many years, its Gap Stewardship Layer was its primary means of inventorying protected areas. This data mainly contained federal and state lands, and was updated periodically by state, then by multi-state region. Working through the Partnership, USGS published its first national inventory as PAD-US version 1 in April 2009, and is now conducting further updates in a coordinated effort with CBI and other Partnership members.

Individual states have varying degrees of protected lands data - some are very thorough, others have only state holdings. There are also multi-state efforts by non-profits, including the Ducks Unlimited CARL system for the upper Great Lakes region, and the TNC Secured Lands data for New England states. You can learn more about these and contribute your own information by going to the Data Portal of this website.

There are six "gaps" in our current data inventory efforts - these are being addressed by the PAD-US Design Project.

1. Funding - there is no assured funding to maintain a complete and current protected lands database of the U.S., and special investment is needed to make the jump from where we are now to the next level.
2. Completeness - we need to extend inventories to the local (city, county, metropolitan) levels, as well as to improve some state's data and some federal data.
3. Accuracy - the spatial accuracy of inventoried lands needs to be improved (possibly through better use of tax parcel data)
4. Standards and Process - standard collection models and processes need to be embraced at state and sub-state levels, to better facilitate a national dataset.
5. Conservation Status Coding - the protected lands inventory needs to more effectively support conservation status codes (e.g., Gap and IUCN scores) and needs an adjudication process to resolve issues in such codes.
6. Main Attributes - more complete and accurate descriptors about protected areas are needed (e.g., recreation access codes, management designations, etc.)

State Heritage Programs - each state has a heritage program office that helps develop and manage critical data for biodiversity planning and protection. Coordinated through NatureServe, many of these heritage programs play important roles in gathering protected lands data and will be part of any PAD-US strategy.

The Nature Conservancy Conservation Measures Program - TNC is investing considerable effort to improve the manner in which it assess conservation effectiveness of all types of land protection. This work includes developing inventories of their own protected lands as well as strategies for larger inventories. TNC staff are closely involved with the PAD-US project.

LandScope America - this new collaboration between NatureServe and National Geographic Society showcases a wide range of conservation information and includes interactive maps. The Landscope project, however, is focused on integrating existing data rather than improving or developing new data.

Conservation Registry - Defenders of Wildlife has developed this web framework to better identify a range of on the ground conservation initiatives in the U.S., particularly those stemming from state wildlife action plans. The Registry may provide opportunities for feeding data into an improved national inventory process.

PAD-US Version 1 is the most complete national inventory as of April 2009. However, version 1 does not have the full attribute design of the PAD-US proposal, nor does it fully implement its robust geodatabase model. It also does not yet include lands below the state level for many states. All of these will be addressed in the development of PAD-US version 2.0 in 2010-2012. A revision to version 1 is anticipated in late 2009, with more new data and many core attributes from the proposed PAD-US design.

In general, 2007-2009. However, source data is updated sporadically, generally at state or regional scales. See the GIS_Source field for the publication year. The proposed future PAD-US data set will have more up to date information.

Go to the USGS GAP web site and choose the file you wish to download - as an ESRI geodatabase, with or without water features, or as in shape file format, with and without water. This site also contains a file with the database tables used to create the coded domains in the geodatabase (Class_Desc, Owner_Desc, Manager_Description, State_FIPS).

We are at an interim stage regarding the treatment of water in PADUS. In the "No Water" version, we have removed all water polygons from the protected areas layer itself. In the future, water in PAD-US will managed in a separate feature class.

For the Version 1, No Water data, we removed water polygons coded as '8101' or 'Water' in the Manag_Desc (Management Designation) field. These are undesignated water polygons, in terms of management. Wild and Scenic Rivers and other designated waters remain in PADUSv1_No_water.

PAD-US version 1 contains the publicly availale data from the older Southeastern Gap layer. However, restrictions may occur in the future if more sensitive data is incorporated into the PAD-US data set.

For the most highly protected areas (GAP 1 or 2) lands, you may use the WDPA_Code and WDPA_NewCode. Otherwise, use the standardized WDPA_Name field (see metadata for field descriptions).