What automated records can I find on this site?
You can find Master Title Plats (MTPs), Oil and Gas Plats, Leasable Resources Plat, and Historical Index (HI) pages including index pages to acquired lands and Mineral Locations and Contests. These are the documents that used to be microfilmed and then made available for review in our Information Access Centers throughout the state.
Where can I find Cadastral Survey plats and Field Notes?
Cadastral Survey plats, Mineral Surveys or Field Notes are not yet available online; however, we are working on getting them online, and in the mean time, can be obtained from the California State Office Information Access Center, (916) 978-4330.
What type of image are these files?
All the images have been scanned and archived as a Tagged Image File Format (tiff or tif). The tif format has been determined to be a high quality image format and was selected by the National Archive as the most widely accepted and preferred image format for scanning and archiving.
What information do I need to find the image I'm looking for?
Over 30,000 MTP and HI pages have been scanned and are searchable by meridian, township, and range (MTR). Once you select the MTR, you will be presented with a table displaying the names of all the images scanned in that selected MTR. If you are uncertain what MTR you need, you may contact the California State Office at (916) 978-4400 for assistance.
What do all the characters mean in the image name?
The file name consists of 15 characters. For example, in the file name ca210090n0150e0-1001.tif, the first two characters "ca" indicate the two-letter state abbreviation, i.e., ca = California. The third and fourth characters "21" are the two-digit Meridian Code. Humboldt Meridian = 15, Mount Diablo Meridian = 21, San Bernardino Meridian = 27, and Gila Salt River Meridian = 14. The fifth, sixth and seventh characters "009" are the three-digit Township number, with leading zeros for townships of single digits. The eighth character "0" is for fractional townships. A "0" represents no fraction, "2" represents a ½ Township. The ninth character "n" is the township direction, n= North, and s= South. The tenth, eleventh and twelfth characters "015" are the three-digit range number, with leading zeros for ranges of single digits. The thirteenth character "0" is for fractional ranges. A "0" represents no fraction and a "2" represents a ½ Range. The fourteenth character "E" is the range direction, E = East and W = West. The fifteenth character "0" is duplicate townships, "0" is for no duplicate and "2" indicates the second of two duplicate township. The four characters after the dash are the Plat Type Code and Page Number.
What are Plat Type Codes?
The Plat Type Code is the last 4 digits of an image name. For example, using the same image name as above, ca210090n0150e0-1001.tif, the last four digits are 1001. The Plat Type Code can be identified easily because it is separated from the rest of the image name by a hyphen ("-"). The 4-digit code is broken down into two parts: the first two digits are the plat type, the second 2 digits are the page number for that plat type. For example the code 1001 is the first page of the MTP. The 10 represents the Plat Type Code for MTP and the 01 represents the page number. A Plat Type Code of 1002 could be a supplemental plat, a continuation remarks sheet, or some other type of supplemental sheet for the original MTP, but indicates that it is page 2. This numbering system holds true for all plat types. Page 10 of an HI would be numbered 2010. The following is a chart of plat type codes and what type of plat or document they represent:
Plat Type Code
Master Title Plat (MTP)
Historical Index (HI)
Acquired Land Historical Index
Mineral Location/Contests Historical Index
Oil & Gas Plat
Leasable Minerals Plat
What software is used to view the images online?
This site utilizes the Acordex Java Image Viewer to view tiff images of MTPs, HIs, and other use plats.
Upon selection of a particular image file, the viewer will open in a new browser window. Within the viewer, you can ZOOM, PAN, SAVE, and PRINT copies of the plats for future use. A guide how to use the Acordex Java Image Viewer can be found by clicking here.