Katharine Macmillan, Viscountess Macmillan of Ovenden

{{short description|British aristocrat (1921-2017)}}

{{More citations needed|date=June 2015}}

{{Use dmy dates|date=September 2020}}

{{Infobox officeholder

| honorific-prefix = The Honourable

| name = Viscountess Macmillan
of Ovenden

| honorific-suffix = DBE

| birth_name = Katharine Margaret Alice Ormsby-Gore

| birth_date = {{birth date|1921|1|4|df=y}}

| death_date = {{Death date and age|2017|1|22|1921|1|4|df=y}}

| spouse = {{marriage|Maurice Macmillan, Viscount Macmillan of Ovenden|22 August 1942|10 March 1984|end=died}}

| father = William Ormsby-Gore, 4th Baron Harlech

| mother = Lady Beatrice Gascoyne-Cecil

| children = {{nowrap|Alexander Macmillan, 2nd Earl of Stockton}}
Joshua Macmillan
Adam Macmillan
Rachel Macmillan
David Macmillan

}}

Katharine Margaret Alice Macmillan, Viscountess Macmillan of Ovenden {{post-nominals|country=GBR|DBE}} (née Ormsby-Gore; 4 January 1921 – 22 January 2017), was the daughter of the 4th Baron Harlech,[http://thepeerage.com/p4608.htm#i46072 The Peerage.com] granddaughter of the 4th Marquess of Salisbury, great-granddaughter of the 10th Marquess of Huntly and daughter-in-law of Prime Minister Harold Macmillan, 1st Earl of Stockton.

On 22 August 1942, she married Conservative politician Maurice Macmillan, making her the daughter-in-law of fellow Conservative politician Harold Macmillan, who would serve as prime minister from 1957 to 1963.

They had five children together:

• 1) Alexander Daniel Alan Macmillan, 2nd Earl of Stockton (born 1943)
• 2) Joshua Edward Andrew Macmillan (1945–1965)
• 3) Adam Julian Robert Macmillan (1948–2016)
• 4) Rachel Mary Georgia Macmillan (1955–1987)
• 5) David Maurice Benjamin Macmillan (born 1957)

She was Vice-Chairman of the Conservative Party in 1968 and was created a Dame Commander of the Order of the British Empire (DBE) in 1974. She became Viscountess Macmillan of Ovenden in February 1984 when her father-in-law, former British prime minister Harold Macmillan, accepted a peerage and was created Earl of Stockton. Her husband died the following month, so never inherited the earldom from his father.

She died on 22 January 2017.[http://announcements.telegraph.co.uk/deaths/210699/macmillan MACMILLAN]