Question: Slane Beg is northwest of a town in what Irish county?

Context paragraphs:
Slane: Slane (Irish: "Baile Shláine" , meaning 'Town of Sláine mac Dela') is a village in County Meath, in Ireland.  The village stands on a steep hillside on the left bank of the River Boyne at the intersection of the N2 (Dublin to Monaghan road) and the N51 (Drogheda to Navan road).  In 2006 Slane's population was 1,099, having grown from 823 in 2002.  The population of the village and the surrounding rural area was 1,587 in 2006, up from 1,336 in 2002.  The village centre dates from the 18th century.  The village and surrounding area contains many historic sites dating back over 5,000 years.

Slane Castle: Slane Castle is located in the town of Slane, within the Boyne Valley of County Meath, Ireland.  The castle has been the family home of the Conyngham family since the 18th century.

Slane Beg: Slane Beg is a townland in County Westmeath, Ireland.  It is located about 7.43 km north–west of Mullingar.

County Roscommon: County Roscommon (Irish: "Contae Ros Comáin" ) is a county in the western region of the Republic of Ireland.  It is also part of the province of Connacht.  It is the 11th largest Irish county by area and 27th most populous.  Its county town and largest town is Roscommon.  Roscommon County Council is the local authority for the county.  The population of the county is 64,436 according to the 2016 census.

The Johnstons: The Johnstons were an Irish close-harmony folk band, founded in Slane, County Meath, Ireland, consisting of Adrienne, Lucy and Michael Johnston.  They began performing in the early 1960s in Slane.

Slane Concert: Slane Concert (often referred to as Slane) is a recurring concert held most years since 1981 on the grounds of Slane Castle near Slane, County Meath, Ireland.  The castle is owned by The 8th Marquess Conyngham, who was known by the courtesy title the Earl of Mount Charles from 1974 until 2009.  Slane lies between Navan and Drogheda, about 45 km northwest of Dublin.  Concerts typically occur on a Saturday in August, from 12:00 to 22:00.  However, the 2011, 2015 and 2017 concerts occurred on the last weekend in May, and the first concert of 2013 took place on 15 June.

County Sligo: County Sligo ( , ) is an Irish county and part of the province of Connacht.  It is located in the Border Region.  Sligo is the administrative capital and largest town in the county.  Sligo County Council is the local authority for the county.  The population of the county is 65,393 according to the 2011 census making it the 3rd most populated county in the province.  It is noted for Benbulben Mountain, one of Ireland’s most distinctive natural landmarks.

Larry Mathews (musician): Larry Mathews is a musician from Glenbeigh in the Irish County Kerry.  He sings and plays Irish Folk, his own compositions as well as Rock and Pop.  He plays Irish Fiddle, Guitar und Bodhrán (the Irish frame drum).  On stage he has played with Christy Moore, the Furey Brothers, The Dubliners, Achim Reichel and many others.  He has recorded with , as guest musician for Chris Evans & , Hannes Wader and with many others.

Sack of Cashel: The Sack of Cashel (also known as the Massacre of Cashel) was a notorious atrocity which occurred in the Irish County of Tipperary in the year 1647, during the Irish Confederate Wars, part of the Wars of the Three Kingdoms.  The town of Cashel was held by the Irish Catholic Confederate's Munster army and was besieged and taken by an English Protestant Parliamentarian army under Murrough O'Brien the Baron of Inchiquin.  The attack and subsequent sack of Cashel was one of the more brutal incidents of the wars of the 1640s in Ireland.

Mullingar: Mullingar ( ; Irish: "An Muileann gCearr" , meaning "the left-handed mill" ) is the county town of County Westmeath in Ireland.  It is the 3rd most populous town in the midlands region with a population of 20,928 in the 2016 census.

Supporting paragraphs: Slane Beg Mullingar
Answer: Westmeath