Cathie;

Elijah [Elias]Martin a great one to hunt down, here you go...Hopefully you can follow my logic and trail.

Married to Nancy Jane Hopper Born 1831 in Indiana to Raleigh Hopper and Rebecca Mallonee/Maloney. The Hopper Family is found in 1850 Census in Ozark County MO.
Then in the Douglas Co census for 1860, 1870, 1880.

Elijah Martin
Birth: 17 JAN 1817 in Indiana
Death: 9 JAN 1891 in Douglas Co., Missouri
Burial: Denlow Cemetery, Cass Township, Douglas Co., Missouri

Marriage Nancy Jane Hopper b: 1831 in Indiana
Married: Between 1850 and 1860.

1880 Douglas Co Census dwelling 354
Name: Elias Martin
Home in 1880: Cass, Douglas, Missouri
Age: 63
Estimated birth year: abt 1817
Birthplace: Indiana
Spouse's name: Nancy J.
Father's birthplace: South Carolina
Mother's birthplace: Kentucky
Occupation: Farming

Household Members: Name Age
Elias Martin 63
Nancy J. Martin 49
Rebecca Hopper 75

1870 Census Douglas Co. MO Dwelling 52
Name: Elias Martin
Home in 1870: Cass, Douglas, Missouri
Age: 53
Estimated birth year: abt 1817
Birthplace: Indiana
Spouse's name: Nancy J.
Occupation: Farming

Household Members: Name Age
Elias Martin 53 Indiana
Nancy J. Martin 39 (unreadable/overwritten)
Rebecca Hopper 65 Kentucky
Issac Hopper 27 Missouri

Name: Elias Martin
Age in 1860: 43
Birth Year: abt 1817
Birthplace: Indiana
Home in 1860: Douglas, Missouri
Post Office: Falling Spring

Household Members: Name Age
Elias Martin 43 M Indiana
Nancy J Martin 29 F Indiana
Francis Martin 22 M Indiana

Accession/Serial #: MO5910__.285 BLM Serial #: MO NO S/N
Patentee: ELIAS MARTIN
Survey
State: MISSOURI
Acres: 160
Metes/Bounds: No

Title Transfer
Issue Date: 8/10/1888
Land Office: Springfield
Authority: May 20, 1862: Homestead EntryOriginal (12 Stat. 392)
Document Nr.: 5423
Misc. Doc. Nr.: 8392
Accession/Serial Nr.: MO5910__.285
BLM Serial Nr.: MO NO S/N

Aliquot Parts Sec./Block Township Range Fract.Section Meridian State Counties (Matches for Cass township-JJR )
----------------------------------------------------------
SWSW 22/ 27-N 13-W No 5th PM MO Douglas
N½NW 27/ 27-N 13-W No 5th PM MO Douglas
SENW 27/ 27-N 13-W No 5th PM MO Douglas

I'm convinced that this Elias Martin is the Elijah Martin on your list. I find no connection to Illinois or Civil War service with an Illinois unit. He clearly was in Douglas County at the begining of the war and to have him enlist in a Illinois unit would be unusual. There is an Elijah Martin Born in Indiana that lived in Ortegwa IL married to a Nancy that I think is more likely the one you refer to.

However Here is the good news....

There is a denied pension application from a Nancy J. Martin filed Aug 27 1892 as a widower, #557704 to the state of Missouri for an Elijah Martin that served with Company D, Webster County Missouri Home Guards. Following that lead on the Missouri SOS site you will find indeed a listing for Elijah Martin, enlisting June 12 1861 in Taney County Missouri, mustered out Nov 1, 1861, in the Webster County Home Guard. Pension was denied because this was not a federalized unit. Taney County as you know is a border county of Douglas County and near the area of Ozark county that Douglas county was subsequently taken from. It is also near the Hopper homestead. Also note that Webster County was also a border county (to the north of Douglas) and that Douglas Co was relatively new at the onset of the war. Given this info I think this is the most likely scenario and service.

John R.