The graphic links below show portions of Historic California Maps.  You can click on each map to see a larger version of the map.  Emphasis added when needed to show the viewer the location of Ryer Island by Steamboat Slough, as the waterways were usually not labeled in the maps.  Note that the waterway currently known as Steamboat Slough was a primary route between San Francisco and Sacramento in the 1850's to at least 1930's, since it was a more direct and therefore faster route.
Added Nov 2008:  1935 Soils map: Large file, so may open slowly when you click on the photo below	Compare the historic maps below with this recent Delta map provided in the documentation regarding the "Delta Vision" group reviewing how to revise the Delta to change water flows.  Note the map labels both Ryer Islands!
Portion of 1851 Miner's Map	Portion of 1855 Secretary of War Map
Portion of 1860 map of the counties of California	Portion of 1866 California private Land Grants-surveyed early 1860's
Portion of 1871 Map	Portion of 1873 map
Portion of 1895 Cyclers map!  Ferries were used for cycling from Fairfield up to Sacramento	Portion of 1896 Blum map for reilroads
Portion of 1896 county map which shows major water route used at that time, to Sacramento	Portion of 1897 Rand McNally map
Portion of 1901 Southern Pacific Railway map	Portion of 1908 California Trade map