- 1 Tuguegarao — The provincial capital
- 2 Lal-lo — Rural municipality housing the new Cagayan North International Airport. The guide also covers the nearby towns of Gattaran and Lasam.
- 3 Aparri — Northern terminus of the Cagayan Valley Road
- 4 Baggao
- 5 Peñablanca
- 6 Claveria—Santa Praxedes — A pair of towns at the boundary with Ilocos Norte
- 7 Santa Ana (Cagayan) — Gateway to Palaui Island
Cagayan has been inhabited since prehistoric times, through anthropological and archaeological finds such as the Callao Man, and the Lal-lo and Gattaran Shell Middens. The first inhabitants are hunter-gatherers specialized in hunting mollusks; they were believed to be Negritos (Atta) based on anthropological evidence. Migrations of Austronesians (or Malays), the ancestors of most of the native groups such as the Ibanag, Gaddang, Itawes and some Igorot tribes, have driven the Negritos into the mountains at the eastern coast.
Civilizations have thrived long in the province before Spanish colonization. Locals have traded with the Chinese and Japanese, and there are also records of a Japanese pirate kingdom in Cagayan, which lasted until 1582.
The Spaniards first came in 1581, on an expedition to explore the areas north of the Caraballo mountain range and east of the Cordillera Central, and convert the locals to Catholicism. Conquistador Juan de Salcedo, sent to explore the coast of northern Luzon, also landed at the areas now occupied by the towns of Pamplona and Aparri.
Cagayan used to cover all of the Cagayan Valley region during Spanish times. Founded in 1583 by royal decree, it included all of present-day Cagayan Valley, Batanes, and parts of the provinces of Kalinga and Apayao, until the new provinces were carved out from 1839 afterwards. The original capital was in Lal-lo, then the town of Nueva Segovia, also the namesake of the Roman Catholic archdiocese which now has its seat in Vigan and includes the provinces of Ilocos Norte, Ilocos Sur, Abra, and Benguet.
Cagayan has all of the three tropical climate regimes of the Philippines, but the two most prominent are the tropical monsoon and the tropical savanna regimes.
- The tropical savanna climate zone mostly occupies the basin of the eponymous Cagayan River (except at its estuary), which includes the capital at Tuguegarao. There is a dry season from January to April, and temperatures can hit the 40 °C (104 °F) mark.
- Most of the province have a tropical monsoon climate, which has a shorter dry season, and low possibility of extreme daytime highs.
- Mountains at the eastern coast have a rainforest climate, which transitions into temperate oceanic at about 1,000 m (3,300 ft) above sea level.
The province is at the heart of the typhoon belt, and has weather stations that are vital for typhoon tracking. Typhoons generally strike the province during the rainiest months, from August to October.
Cagayan's overall climate is rainy, with a short dry season lasting from either January or February to April. The northeast monsoon (amihan) from Siberia and moist air masses from the Pacific brings much of the rain, and the province generally gets 85 rainy days a year.
Asian Highway 26 (AH26) provides the main road link with Manila, though it is possible to take the Santiago-Tuguegarao Road as a shorter alternative. The same highway also provides the main access from Ilocos Region.
- Magapit Suspension Bridge (Lal-lo) is known as "the Golden Gate of Cagayan." It is Asia's first suspension bridge, built in 1978. It spans the Cagayan River at Lallo and is 760 m long. The hanging bridge links the first and second districts of Cagayan going towards the Ilocos Region by the scenic Patapat Road.
- Kalesa (horse-drawn carrier): In Cagayan, kalesas are common, especially in Tuao and many other municipalities. In Tuguegarao City, they are mixed in traffic with private cars, motorcycles, sidecar motorcycles, jeepneys, trucks, and bicycles.
- Duba Cave (Baggao) is a wet river cave and a swimming cave. Almost all passages with water, which is about 70% of the way to the Skylight Falls, have large breakdowns or walls without handholds along the side so the only way through is to swim. Because of this, you should wear a lifejacket. This will ensure a safe return trip especially after the long swims in.
- Rio Grande de Cagayan (Cagayan River) — the Philippines’ mightiest watercourse — is the longest and widest river in the country. Small streams originating form Balete Pass, Cordillera, Caraballo and the Sierra Madre Mountains meet other streams. It passes from Aparri traversing Isabela as far as Aurora.
- Claveria Coast is called the "Coastal Paradise of the Cagayan North."
- Callao Cave (Penablanca) has seven chambers. It is one of the best known tourist attractions of the province. It is in Barangays Parabba and Quibal, Peñablanca, near Tuguegarao, the capital city of the Province of Cagayan. Callao Cave has a natural cathedral at the first chamber, which was turned into a chapel by the local people. The conditions inside the cave cause stalactites and stalagmites, particularly in the deeper chambers. Every chamber has natural crevices, which let light get in, serving as illumination for the otherwise dark areas.
- Calvary Hills (Iguig) consist of 11 hectares of rolling hills. It features larger-than-life concrete statues in tableau settings of the 14 Stations of the Cross, depicting Jesus Christ’s suffering and death on Mount Calvary.
- Basilica Minore Nuestra Señora de Piat (Piat) ("Primary Pilgrimage Center of the North"): The patroness of Cagayan Valley housed at the Basilica Minore of Our Lady of Piat has become the religious fulcrum of people wanting favors of any kind. Visitors may view her history at the Basilica Museum which has an extensive collection of religious items and Our Lady’s vestments and accessories.
- Bukal ng Buhay (Piat) ("Spring of Life") is said to be a miraculous water that can heal diseases of any kind. It is below the hill where the Basilica of Our Lady of Piat stood.
- Portabaga Falls (Santa Praxedes) A well-developed resort and inn managed by the local government of Santa Praxedes. It has 5 pools catering the needs of different age levels. Local and foreign tourists come for its natural beauty.
- Sta. Ana Beaches — from pristine blue waters and fine sand, to rolling hills and enchanting colonial structures, to mystical caves and endearing people — are dubbed as “Untouched Paradise”, “Gateway to the Pacific”, “Game Fishing Mecca”, “Luzon’s Last Frontier” and “Marine Sanctuary”.
- Calayan Island (Calayan): The island town is a two-hour boat ride from Aparri. It is rich in natural attractions like excellent beaches, archeological sites, endemic flora and fauna, virgin forest, crystal clear blue waters, plus hospitable and gentle people with colorful history.
- Ar-Aro Cave (Gattaran): Nobody from among the old-timers of Barangay Naddungan, with a population of not more than 800, remembers how this cave got its name. Only a few locals, particularly fishermen, know the place. It was discovered by some of their old folks as a fishing ground for eels and araro, a freshwater fish.
- Kalamudinan Falls (Baggao) is 26 km from the center of Santa Margarita, Baggao, Cagayan. More than 100 m high and rich in shrimp (locally called udang) and fishes.
- The Malaueg Church (Rizal) is at the Poblacion of the town. The church was preserved completely by UNESCO and underwent restorations. The church is made entirely of stones that was designed by Spaniards.
- Magapit Protected Landscape (Lal-lo and Gattaran)
- Lal-lo and Gattaran Shell Middens (Lal-lo and Gattaran)
- Palaui Island (Santa Ana)
- El Presidente Beach Resort and Hotel (Buguey)
- Enjoy the yummy giant crabs of Buguey
- Try and indulge with the famous Pancit Batil Patong
- Gakka, a tiny shell that no-one can resist.