Balthazar Walter Foster, 1st Baron Ilkeston1 
He graduated from Erlangen University, Erlangen, GermanyG, with a Doctor of Medicine (M.D.)1 He held the office of Member of Parliament (M.P.) for Chester between 1885 and 1886.1 He was appointed Knight Bachelor in 1886.1 He was member of the General Medical Council between 1887 and 1897.1 He held the office of Member of Parliament (M.P.) for Derby, Ilkeston Division between 1887 and 1910.1 He was awarded the Gold Medal of the British Medical Association.1 He was appointed Fellow, Royal College of Physicians, London (F.R.C.P.)1 He was appointed Privy Counsellor (P.C.) in 1906.1 He was created 1st Baron Ilkeston, of Ilkeston, co. Derby [U.K.] on 14 July 1910.1
Children of Balthazar Walter Foster, 1st Baron Ilkeston and Emily Martha Sargant
- unknown daughter Foster1
- unknown daughter Foster1
- unknown son Foster1 b. b 1867
- Balthazar Stephen Sargant Foster, 2nd Baron Ilkeston1 b. 31 Aug 1867, d. 4 Jan 1952
- Hon. Millicent Chance Foster+1 b. 1875, d. 1961
- [S21] L. G. Pine, The New Extinct Peerage 1884-1971: Containing Extinct, Abeyant, Dormant and Suspended Peerages With Genealogies and Arms (London, U.K.: Heraldry Today, 1972), page 155. Hereinafter cited as The New Extinct Peerage.
Balthazar Foster1 
He lived at Drogheda, County Louth, IrelandG.1
Child of Balthazar Foster and Marian Green
- Balthazar Walter Foster, 1st Baron Ilkeston+1 b. 17 Jul 1840, d. 31 Jan 1913
- [S21] L. G. Pine, The New Extinct Peerage 1884-1971: Containing Extinct, Abeyant, Dormant and Suspended Peerages With Genealogies and Arms (London, U.K.: Heraldry Today, 1972), page 155. Hereinafter cited as The New Extinct Peerage.
Thomas Foster1 
He lived at Beaulieu, Hampshire, EnglandG.1
Child of Thomas Foster and Hannah Smith
- Balthazar Foster+1 b. 1813, d. 1862
- [S21] L. G. Pine, The New Extinct Peerage 1884-1971: Containing Extinct, Abeyant, Dormant and Suspended Peerages With Genealogies and Arms (London, U.K.: Heraldry Today, 1972), page 155. Hereinafter cited as The New Extinct Peerage.
Robert Foster1 
He lived at Beaulieu, Hampshire, EnglandG.1
Child of Robert Foster and Catherine Farthing
- Thomas Foster+1 b. 1783
- [S21] L. G. Pine, The New Extinct Peerage 1884-1971: Containing Extinct, Abeyant, Dormant and Suspended Peerages With Genealogies and Arms (London, U.K.: Heraldry Today, 1972), page 155. Hereinafter cited as The New Extinct Peerage.
Thomas Foster1 
Child of Thomas Foster
- Robert Foster+1 b. 1747
- [S21] L. G. Pine, The New Extinct Peerage 1884-1971: Containing Extinct, Abeyant, Dormant and Suspended Peerages With Genealogies and Arms (London, U.K.: Heraldry Today, 1972), page 155. Hereinafter cited as The New Extinct Peerage.
Catherine Farthing1
From 1782, her married name became Foster.1
Child of Catherine Farthing and Robert Foster
- Thomas Foster+1 b. 1783
- [S21] L. G. Pine, The New Extinct Peerage 1884-1971: Containing Extinct, Abeyant, Dormant and Suspended Peerages With Genealogies and Arms (London, U.K.: Heraldry Today, 1972), page 155. Hereinafter cited as The New Extinct Peerage.
Hannah Smith1
She lived at Ashurst Lodge, 2-4 St. Efrides Road, Torquay, Devon, England.1 From 1805, her married name became Foster.1
Child of Hannah Smith and Thomas Foster
- Balthazar Foster+1 b. 1813, d. 1862
- [S21] L. G. Pine, The New Extinct Peerage 1884-1971: Containing Extinct, Abeyant, Dormant and Suspended Peerages With Genealogies and Arms (London, U.K.: Heraldry Today, 1972), page 155. Hereinafter cited as The New Extinct Peerage.
Marian Green1
From 1839, her married name became Foster.1
Child of Marian Green and Balthazar Foster
- Balthazar Walter Foster, 1st Baron Ilkeston+1 b. 17 Jul 1840, d. 31 Jan 1913
- [S21] L. G. Pine, The New Extinct Peerage 1884-1971: Containing Extinct, Abeyant, Dormant and Suspended Peerages With Genealogies and Arms (London, U.K.: Heraldry Today, 1972), page 155. Hereinafter cited as The New Extinct Peerage.
J. Green1
Child of J. Green
- [S21] L. G. Pine, The New Extinct Peerage 1884-1971: Containing Extinct, Abeyant, Dormant and Suspended Peerages With Genealogies and Arms (London, U.K.: Heraldry Today, 1972), page 155. Hereinafter cited as The New Extinct Peerage.
Emily Martha Sargant1
From 25 August 1864, her married name became Foster.1 After her marriage, Emily Martha Sargant was styled as Baroness Ilkeston on 14 July 1910.
Children of Emily Martha Sargant and Balthazar Walter Foster, 1st Baron Ilkeston
- unknown daughter Foster1
- unknown daughter Foster1
- unknown son Foster1 b. b 1867
- Balthazar Stephen Sargant Foster, 2nd Baron Ilkeston1 b. 31 Aug 1867, d. 4 Jan 1952
- Hon. Millicent Chance Foster+1 b. 1875, d. 1961
- [S21] L. G. Pine, The New Extinct Peerage 1884-1971: Containing Extinct, Abeyant, Dormant and Suspended Peerages With Genealogies and Arms (London, U.K.: Heraldry Today, 1972), page 155. Hereinafter cited as The New Extinct Peerage.
