Below is a summary of library districting in Idaho.
| 1919 | | Pierce – Forms as a quasi-school-community library in Clearwater County. |
| 1951 | September 5 | Snake River School-Community Library – Forms in Bingham County. |
| 1952 | | Sugar Salem School-Community Library – Forms in Madison County. |
| 1955 | July 27 | Grace – Forms with the same boundaries as Commissioners District 3 in Caribou County. |
| | September 8 | Council Valley – Forms with the same boundaries as School District 13 in Adams County. |
| 1956 | November 6 | Boundary County – Forms with the same boundaries as Boundary County. |
| 1958 | March 11 | Oneida County – Forms with the same boundaries as Oneida County. |
| | May 3 | Latah County – Forms with the same boundaries as Latah County, except for the city of Moscow. |
| | July 29 | Portneuf – Forms with the same boundaries as School District 25 in Bannock County, except for the city of Pocatello. |
| | August 12 | Madison – Forms with the same boundaries as Madison County, except for Sugar-Salem School Community Library District. |
| | August 12 | Nez Perce County – Forms with the same boundaries as Nez Perce County, except for the city of Lewiston. |
| | September 5 | Bear Lake County – Forms with the same boundaries as Bear Lake County. |
| 1962 | May 22 | Lewis County – Forms with the same boundaries as Lewis County. |
| | June 5 | Lost River Community – Forms with the same boundaries as Butte County. |
| 1964 | May 11 | Kuna School Library – Forms in southwest Ada County. |
| 1965 | April 12 | Boise Basin – Forms in the eastern portion of Boise County. |
| 1966 | January 24 | Valley of the Tetons – Forms in the southern portion of Teton County. The remainder of the county joins the district on October 13, 1976. |
| | August 22 | Midvale – Forms with the same boundaries as School District 433 in Washington County. |
| | November 8 | Benewah County – Forms with the same boundaries as Benewah County, except for St. Maries and Plummer. |
| | November 8 | Clearwater County – Forms with the same boundaries as Clearwater County, except Pierce District and Elk River School-Community Library. |
| | November 16 | South Bannock – Forms with the same boundaries as Bannock County, except for the city of Pocatello and Portneuf District. |
| | December 6 | Freemont County – Forms with the same boundaries as Freemont County, except for Ashton and St. Anthony. |
| 1967 | July 10 | Richfield – Forms in the northern portion of Lincoln County. |
| | November 27 | Forms in the southwestern corner of Shoshone County. |
| 1968 | December 9 | Little Wood River – Forms in the eastern portion of Blaine County. |
| | December 17 | Eagle – Forms with the same boundaries as the Eagle Water and Fire District in Ada County. Dissolves and is absorbed by the city of Eagle on May 31, 1974. |
| 1969 | February 10 | Minidoka – Forms in the eastern portion of Minidoka County. Dissolved on May 13, 1986. |
| 1971 | December 13 | Horseshoe Bend – Forms in the southwestern portion of Boise County. |
| 1972 | September 13 | Mackay – Forms in the southwestern portion of Custer County. |
| | October 19 | Camas County – Forms with the same boundaries as Camas County. |
| | November 7 | Franklin County – Forms with the same boundaries as Franklin County, except for Preston. |
| 1973 | January 8 | Jefferson County – Forms in a portion of Jefferson County, except for Ririe, Rigby, Lewisville, and Roberts. |
| | August 1 | Oakley – Forms in the southwestern portion of Cassia County. |
| | November 13 | Cambridge – Forms with the same boundaries as the Cambridge School District in Washington County. |
| | December 1 | Eastern Bonner – Forms in the eastern two-thirds of Bonner County, except for Sandpoint. Sandpoint dissolves and is absorbed by the district on December 19, 1983. |
| 1974 | May 31 | Eagle – Dissolves and is adsorbed by the city of Eagle. |
| | July 1 | Rockland School-Community Library – Forms in Power County. |
| | August 27 | Meridian – Forms in the west-central portion of Ada County, except for the city of Meridian. The city of Meridian joins the district on August 26, 1975. |
| | December 16 | Eastern Owyhee – Forms with boundaries similar to those of the Grandview School District in Owyhee County. |
| | December 16 | Northside – Forms in an area north of Wallace in Shoshone County. Dissolves in 1980. |
| 1975 | August 26 | Meridian – The city of Meridian joins the Meridian District. |
| | October 28 | Hayden Lake – Forms in an area north of Coeur d’Alene in Kootenai County. Dissolves into the Community Free Library District (CLFD) on September 30, 1986. |
| | December 15 | Pinehurst-Kingston – Forms in the western portion of Shoshone County. |
| 1976 | March 16 | Kootenai County – Forms with the same boundaries as Kootenai County, except Coeur d’Alene, Post Falls, Harrison, Rathdrum, Athol, Spirit Lake, and Hayden Lake District. The city of Rathdrum joins the district on October 1, 1982. Dissolves into CFLD on September 30, 1986. |
| | October 13 | Valley of the Tetons – The remainder of Teton County joins the district. |
| | December 13 | Clark County – Forms with the same boundaries as Clark County. |
| 1977 | November 15 | Wilder – Forms with the same boundaries as the Wilder School District in Canyon County. |
| 1978 | July 6 | American Falls – Forms with the same boundaries as Power County. |
| | November 13 | Garden Valley – Forms in the remainder of Ada County, except for Boise Basin and Horseshoe Bend districts. |
| 1979 | December 10 | Bruneau – Forms in the eastern quarter of Owyhee County. |
| 1980 | | Northside – Dissolves. |
| | May 12 | Bonneville County – Forms with the same boundaries as Bonneville County, except for the city of Idaho Falls. |
| | May 15 | Ola – Forms in the area surrounding Ola in Gem County. |
| 1982 | October 1 | Kootenai County – The city of Rathdrum joins the district. |
| 1983 | October 17 | Lizard Butte – Forms in and around the city of Marsing in Owyhee and Canyon Counties. |
| | December 19 | East Bonner – Sandpoint dissolves and is absorbed. |
| 1984 | August 30 | Ada County – Forms from the remainder of Ada County, except for Boise, Eagle, Garden City, Meridian District, and Kuna School-Community Library District. |
| 1985 | September 19 | Nampa Surburban – Forms in the area surrounding the city of Nampa. Dissolves on July 1, 1986. |
| | October 1 | Consolidated Free Library District – Forms with the same boundaries as Kootenai County, except for Coeur d’Alene, Harrison, and Post Falls. |
| 1986 | May 6 | Jefferson County – The Grant area is added to the district. |
| | May 13 | Minidoka – Dissolves. |
| | May 20 | Hansen – The Hansen City Library dissolves into a district with the same boundaries as the school district in Twin Falls County. |
| | July 1 | Nampa Suburban – Dissolves. |
| | September 30 | Hayden Lake – Dissolves into CFLD. |
| | September 30 | Kootenai County – Dissolves into CFLD. |
| | November 4 | Unsuccessful attempt to add the city of Priest River and the southwestern part of Bonner County to the East Bonner District. |
| 1991 | December 17 | Nez Perce Free Library District and Lewis County Free Library District consolidate to form the Nez Perce-Lewis County Libraries. |
| 1992 | November 3 | North Bingham Library District – City of Shelley dissolves into a district with the combined boundaries of Firth and Shelley school districts. |
| 1993 | November 2 | Latah County – City of Moscow joins the district after many years of operating jointly by contract. |
| | November 9 | Unsuccessful attempt to form Gem District, with the same boundaries as Gem County, except for the city of Kellogg and the Clarkia District. |
| 1994 | May 24 | Second unsuccessful attempt to form a district in Shoshone County. |
| | November | Harrison Library – Joins the Kootenai County Libraries. |
| 1996 | May | Pinehurst-Kingston – Consolidates with Kootenai County Libraries and the Salmon Public Library to form the Lemhi County District Library. |
| 1998 | May | Stanley District – Forms in Custer County. |
| | May | Nez Perce-Lewis Counties Library District – Annexation of Kooskia in northern Idaho County. The district’s name changes from the Nez Perce-Lewis Counties Library District to the Prairie River Library District. |
| 1999 | May | Aberdeen Library District – Is established. |
| | August | Meadows Valley Library District – Is established in New Meadows. |
| | November | Prairie River District – Annexation of Kamiah. |
| | November | Priest Lake Library District – Is established. |
| 2002 | November | Freemont County Consolidation – Ashton and St. Anthony. |
| 2003 | November | West Bonner Library District – Annexation |
| 2017 | November 27 | Donnelly Public Library District – Forms in Valley County, using the same boundaries as the fire district, about 1/3 of the county. |
| 2018 | May 18 | Gooding Library District – Forms using the same boundaries as the fire district and including the city of Gooding. |
| 2022 | November | Homedale District Library – Is Established. |