River Boyne in the context of "Trim, County Meath"

Shown here are all the major rivers and tributaries of Ireland with their lengths (in kilometres and miles). Starting with the Northern Ireland rivers, and going in a clockwise direction, the rivers (and tributaries) are listed in regard to their entry into the different seas: the Irish Sea, the Celtic Sea and the Atlantic Ocean. Also shown are two tables. Table 1 shows the longest rivers in Ireland with their lengths (in kilometres and miles), the counties they flow through, and their catchment areas (in square kilometres). Table 2 shows the largest rivers in Ireland (by mean flow) in cubic metres per second.

The longest river in Ireland is the River Shannon, at 360.5 kilometres (224.0 mi). The river develops into three lakes along its course, Lough Allen, Lough Ree and Lough Derg. Of these, Lough Derg is the largest. The Shannon enters the Atlantic Ocean at the Shannon Estuary. Other major rivers include the River Liffey, River Lee, River Swilly, River Foyle, River Lagan, River Erne, River Blackwater, River Nore, River Suir, River Barrow (The Three Sisters), River Bann, River Slaney, River Boyne, River Moy and River Corrib.

County Meath (/miːð/ MEEDH; Irish: Contae na Mí or simply an Mhí, lit. 'middle') is a county in the Eastern and Midland Region of Ireland, within the province of Leinster. It is bordered by County Dublin to the southeast, Louth to the northeast, Kildare to the south, Offaly to the southwest, Westmeath to the west, Cavan to the northwest, and Monaghan to the north. To the east, Meath also borders the Irish Sea along a narrow strip between the rivers Boyne and Delvin, giving it the second shortest coastline of any county. Meath County Council is the local authority for the county.

Meath is the 14th-largest of Ireland's 32 traditional counties by land area, and the 8th-most populous, with a total population of 220,826 according to the 2022 census. The county town and largest settlement in Meath is Navan, located in the centre of the county along the River Boyne. Other towns in the county include Trim, Kells, Laytown, Ashbourne, Dunboyne, Slane and Bettystown.

Newgrange (Irish: Sí an Bhrú) is a prehistoric monument in County Meath in Ireland, placed on a rise overlooking the River Boyne, eight kilometres (five miles) west of the town of Drogheda. It is an exceptionally grand passage tomb built during the Neolithic Period, around 3100 BC, making it older than Stonehenge and the Egyptian pyramids. Newgrange is the main monument in the Brú na Bóinne complex, a World Heritage Site that also includes the passage tombs of Knowth and Dowth, as well as other henges, burial mounds and standing stones.

Newgrange consists of a large circular mound with an inner stone passageway and cruciform chamber. Burnt and unburnt human bones, and possible grave goods or votive offerings, were found in this chamber. The monument has a striking façade made mostly of white quartz cobblestones, and it is ringed by engraved kerbstones. Many of the larger stones of Newgrange are covered in megalithic art. The mound is also ringed by a stone circle. Some of the material that makes up the monument came from as far as the Mournes and Wicklow Mountains. There is no agreement about its purpose, but it is believed it had religious significance. It is aligned so that the rising sun on the winter solstice shines through a "roofbox" above the entrance and floods the inner chamber. Several other passage tombs in Ireland are aligned with solstices and equinoxes, and Cairn G at Carrowkeel has a similar "roofbox". Newgrange shares similarities with some other Neolithic monuments in Western Europe; especially Gavrinis in Brittany, which has a similar preserved facing and large carved stones, Maeshowe in Orkney, with its large corbelled chamber, and Bryn Celli Ddu in Wales.

Brú na Bóinne (Irish: [ˈbˠɾˠuː n̪ˠə ˈbˠoːn̠ʲə], "mansion or palace of the Boyne"), also called the Boyne Valley tombs, is an ancient monument complex and ritual landscape in County Meath, Ireland, located in a bend of the River Boyne. It is one of the world's most important Neolithic landscapes, comprising at least ninety monuments including passage tombs, burial mounds, standing stones and enclosures. The site is dominated by the passage tombs of Newgrange (Sí an Bhrú), Knowth (Cnogbha) and Dowth (Dubhadh), built during the 32nd century BC. Together these have the largest assemblage of megalithic art in Europe. The associated archaeological culture is called the "Boyne culture".

Brú na Bóinne is also an important archaeoastronomical site; several of the passage tombs are aligned with the winter solstice and equinoxes. The area continued to be a site of ritual and ceremonial activity in the later Bronze Age and Iron Age. In Irish mythology, the tombs are said to be portals to the Otherworld and dwellings of the deities, particularly The Dagda and his son Aengus. They began to be studied by antiquarians in the 18th century, and archaeological excavations began in the 20th century, when some of the passage tombs underwent restoration.

The Laigin, modern spelling Laighin (Irish pronunciation: [ˈl̪ˠəinʲ]), were a Gaelic population group of early Ireland. They gave their name to the Kingdom of Leinster, which in the medieval era was known in Irish as Cóiced Laigen, meaning "Fifth/province of the Leinstermen" (Modern Irish Cúige Laighean), where their descendants ruled till the 17th century. Their territory, located in south-east Ireland, is thought to have once extended from the River Shannon to the River Boyne. The surnames of those descended from the Laigin are still counted amongst the most numerous in Ireland.

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). As of the 2022 census, Slane's population was 1,445. The village and surrounding area contains many historic sites dating back over 5,000 years. The village centre, as it is laid-out today, dates mainly from the 18th century. The village is in a townland and civil parish of the same name.

Knowth (/ˈnaʊθ/; Irish: Cnóbha) is a prehistoric tomb overlooking the River Boyne in County Meath, Ireland. It comprises a large passage tomb surrounded by 17 smaller tombs, built during the Neolithic era around 3200 BC. It contains the largest assemblage of megalithic art in Europe. Knowth is part of the Brú na Bóinne complex, a World Heritage Site that also includes the similar passage tombs of Newgrange and Dowth.

After its initial period of use, Knowth gradually became a ruin, although the area continued to be a site of ritual activity in the Bronze Age. During the early Middle Ages, a royal residence was built on top of the great mound, which became the seat of the Kings of Knowth or Northern Brega. Archaeologist George Eogan led an extensive investigation of the site from the 1960s to 1980s, and parts of the monument were reconstructed.

Mornington (Irish: Baile Uí Mhornáin, meaning 'town of the mariner') is a coastal village on the estuary of the River Boyne in County Meath, Ireland approximately 5 km downriver from the centre of Drogheda. Together with the neighbouring villages of Laytown, Bettystown and Donacarney, it comprises the urban area of Laytown–Bettystown–Mornington–Donacarney with a combined population of 15,642 at the 2022 census.

The large townland of 1,223 acres (4.95 km) is bound on the north by the River Boyne estuary and on the east by the Irish Sea. The townland extends along the seashore to Bettystown village and includes part of that village up to and including The Neptune Hotel. The townland, part of the civil parish of Colpe, touches on other townlands: Betaghstown to the south, Colp East and Colp West to the west and Donacarney Great and Donacarney Little to the south and west. Stameen lies to the west. Baltray, Beaulieu and Banktown lie across the Boyne.

Baltray (historically Ballytra, from Irish: Baile Trá, meaning 'town of the beach') is a village and townland in County Louth, Ireland. It sits on the northern shore of the River Boyne estuary.