Question: Where is the castle, at which Iye Mackay, 4th of Strathnaver was murdered, located?

Context paragraphs:
Iye Du Mackay, 12th of Strathnaver: Iye Du Mackay, 12th of Strathnaver was the chief of the Clan Mackay, a Highland Scottish clan, from 1550 to 1572.

4th Maneuver Enhancement Brigade: The 4th Maneuver Enhancement Brigade (4th MEB) was a United States Army brigade located at Fort Leonard Wood, Missouri, subordinate to the 1st Infantry Division since its activation on October 16, 2008.  The 4th MEB was one of two active duty Maneuver Enhancement Brigades (the 1st MEB is at Fort Polk, Louisiana).  The Brigade was tasked to improve the movement capabilities and rear area security for commanders at division level or higher.  This was the only brigade in Fort Leonard Wood that is part of FORSCOM.  The 4th Maneuver Enhancement Brigade inactivated on June 17, 2015.

4th Sustainment Command (Expeditionary): The 4th Sustainment Command (Expeditionary) (ESC) is a subordinate command of 79th Sustainment Support Command.  The 4th ESC is located in San Antonio, Texas.  The command comprises 54 subordinate units and has command and control of more than 6,500 Army Reserve soldiers throughout Texas, Oklahoma, Arkansas, and New Mexico.  The 4th ESC provides trained and ready forces in support of global contingency operations.  On order, the 4th ESC is prepared to deploy and provide command and control to all assigned, attached, and operationally controlled units and will provide sustainment planning, guidance and support to forces in the area of operations.

Iye Mackay, 4th of Strathnaver: Iye Mackay, 4th of Strathnaver (died 1370) was the chief of the ancient Clan Mackay, a Scottish clan of the Scottish Highlands.  He was murdered along with his eldest son Donald at Dingwall Castle during a feud with the Earl of Sutherland, chief of the Clan Sutherland.

Chiefs of Clan Mackay: The Clan Mackay is a highland Scottish clan.  The clan chief of Clan Mackay has from early times been designated "of Strathnaver".  The chief was also from early times seated at Castle Varrich but later moved to Tongue House in Tongue, Highland.  In the 17th century the chief of Clan Mackay was made Lord Reay.  The following is a list of the chiefs of Clan Mackay.

Iye Roy Mackay, 10th of Strathnaver: Iye Roy Mackay, 10th of Strathnaver (died 1517) was a chief of the ancient Clan Mackay, a Scottish clan of the Scottish Highlands.

Dingwall Castle: Dingwall Castle was a medieval fort and royal castle in the town of Dingwall, eastern Ross-shire, Scotland.

4th Tank Battalion: 4th Tank Battalion (4th Tanks) is an armored battalion of the United States Marine Corps reserve.  Their primary weapon system is the M1A1 Abrams main battle tank and they are part of the 4th Marine Division and Marine Forces Reserve.  The unit headquarters is at the Navy and Marine Corps Reserve Center San Diego, California, but other units in the battalion are located throughout the United States.  With six lettered companies, 4th Tank Battalion is the largest Marine tank battalion.

John George MacKay: John George MacKay (November 6, 1893 – October 21, 1974) was a farmer and political figure on Prince Edward Island.  He represented 4th Prince in the Legislative Assembly of Prince Edward Island from 1949 to 1966 as a Liberal.  MacKay was the 20th Lieutenant Governor of Prince Edward Island, serving from October 6, 1969 to October 24, 1974.

4th &amp; B'way Records: 4th & B'way Records (pronounced and spelled out completely as Fourth and Broadway Records in the UK) was a US-based subsidiary of Island Records that specialized in street-oriented music such as hip hop.  Established in 1984, it was the flagship label of the Island Trading Company, the independent-distribution parent company of Island's other record labels that operated in the US.  However, 4th & B'way was not distributed through major-label channels—the flagship Island label was distributed by Atlantic Records at that time—until the label and distribution company were acquired by PolyGram Records in 1989, when Island Trading became a unit of PolyGram Group Distribution and was renamed Independent Label Sales (ILS).  It was also one of several US-based Island labels that were named after nearby New York City streets when Island's US headquarters were located at 14 East 4th Street in Manhattan, the same building that held the legendary Greenwich Village branch of Tower Records, and also nearby at 400 Lafayette Street.  When Island moved its headquarters to the Worldwide Plaza Building at 825 8th Avenue in 1995, where PolyGram's US headquarters were also located, the empty 4th Street offices became the headquarters of V2 Records.

Supporting paragraphs: Iye Mackay, 4th of Strathnaver Dingwall Castle
Answer: Dingwall, eastern Ross-shire, Scotland