The year of Loon's founding as a community has not been ascertained due to the dearth of official documents. The earliest year to reckon is 1610 when a nucleus Christian community in the coastal village of Napo allegedly resulted from the ministering activities of the Jesuit friars who came to the Philippines more than 85 years earlier.
Church records, however, show that the first parish priest, also a Jesuit, was installed in 1753. The Recollect priests took over the administration of the local church in the late 1760s, but it was only in around 1855 when the imposing stone church of the Our Lady of Light (Birhen sa Kasilak) was completed.
Since 1753, more than 70 priests had served the parish. Today, Loon has five Catholic parishes, the last one (Parish of Our Lady of Peace and Good Voyage) having been established on November 19, 2000.
A 200-year gap exists between the emergence (in historical records) of the community in Napo in 1610 and the installation of Tomas Sevilla in 1810 as Loon’s first town executive. Then addressed as ‘cabeza de barangay’, the municipal mayor was called ‘capitan’ and ‘presidente municipal’ in the ensuing years.
Thirty-two mayors had served the municipality, excluding the incumbent, mayor, Dr. Lloyd Peter M. Lopez. At least three town heads served for more than one term, namely, Vivencio Nazareno (1916-22 and 1928-31); Geronimo Lituañas (appointed, 1946-47 and elected, 1948-51); and Wilfredo Caresosa (1980-86 and 1988-98).
Loon always figures prominently in the political history of the province. Towards the end of the 19th century when the Americans first set foot on Bohol and were met by resistant forces of the local guerrillas opposed to another foreign dominion, Loon was the first town burned by the aggressors in an effort to subdue the reluctant natives.
Just before the century ended, Mariano Sumatra, a.k.a. Mariano “Anoy” Datahan, a native of Barangay Canhangdon Occidental, founded the Eskaya community in Bayabas, Guindulman which later spread to Taytay, Duero. Although not a cultural minority group, the Eskaya has its own system of doing things including the use of an alphabet mostly consisting of symbols representing nature and parts of the human body.
In about 1900, when enmity towards the foreigners subsided, an American engineer visited Loon and described it as a fertile plateau planted with coconut, corn and tobacco, and a progressive town of 16,000 people. He wrote about the imposing structures of the town like the church and convent, stone stairway or Inang-angan, and wharf; children going to school; an affluent community with well-kept environs; and a spring flowing from a cave on the northern edge of the town, after which the name Loon (from ‘nag-loon’, or the merging of freshwater and saltwater) was coined.
In 1903, the first official count of inhabitants was conducted nationwide. Loon’s population was described as fairly large at 18,114 residents. At that time, no other Bohol municipality, including Tagbilaran, registered more than 10,000 residents.
On September 27, 1942, amid the raging US-Japan war, the MoalongRiver that dissects the municipality into the northern and southern parts, became mute witness to the most successful ambush mounted against the Japanese imperial forces by the Boholano guerrillas led by Vicente T. Cubero, a.k.a. Captain Francisco Salazar. Considered the hero of the Battle of Moalong, Salazar claimed to have his family roots in Barangay Pondol. It was Juan ‘Aning’ Relampagos, a former member of the United States Armed Forces in the Far East (USAFE), who brought Salazar to Bohol. Relampagos disguised himself as a trader sailing between Mindanao and the Visayan islands. He met Salazar while plying his goods in the southern towns of Leyte. Relampagos later became municipal mayor and member of the provincial board. The war exploits of Cubero are described in the book entitled "Boholano Guerrillas in Action" that was written by Pio B. Ferandos, former Cebu RTC judge and Loon mayor.
In the years following the Second World War, prominent Loonanons became active participants in charting the development of the province and the country as well. Among them are Natalio P. Castillo, Executive Secretary to Pres. Carlos P. Garcia and member of the House of Representatives; Ramon Lapez, another House member; Ricardo Miranda, governor of the then only Davao province; Fermin Mesina, commercial attaché to Japan and Vietnam; Purisimo R. Castillo, commercial attaché to Spain; Rene Lopez Relampagos, Bohol’s youngest governor; current Budget Undersecretary Mario Relampagos; and Romulo L. Neri, former Secretary of Economic Planning and Director General of the National Economic and Development Authority (NEDA) who is currently the president of the Social Security System (SSS).
September 8, 1597 (unconfirmed) - the image of the Our Lady of Light was reportedly enthroned in a church in Butuan, Agusan del Norte before it was brought to Bohol, away from the marauding Moro bandits. In 1610 (unconfirmed), Fray Pedro Lopez, SJ and company allegedly brought the Kasilak image to Loon where it was warmly received and enthroned.
June 22, 1753 - establishment of Loon as a Spanish mission or "visita"; founding of the Parroquia de la Nuestra Señora de la Luz or Our Lady of Light Parish with Fray Manuel de Elizalde, a Jesuit, as the first parish priest.
1768 - the Jesuits ceded administration of the parish to the Recollects. Years later, the image of the Kasilak was permanently enthroned in the present church of Loon which was completed in around 1855.
1810 - assumption into office of Tomas Sevilla, the first town mayor, then called ‘cabeza de barangay’. He served for 15 years.
1855 - completion of the construction of the Our Lady of Light (Birhen sa Kasilak) Church
About 1899-1900 - the burning of Loon by the Americans to subdue the alleged remaining members of an anti-American movement in Bohol.
March 14, 1900 - Major H.C. Hale and the B and C companies of the 44th Volunteer Infantry sailed for Bohol from Iloilo aboard the transport Elcano. With them was George Percival Scriven, who was particularly interested in the establishment of a Loon-Argao cable communications linkage, which was later accomplished.
April 2, 1900 - George Percival Scriven, in his diary, wrote that Loon was a fertile plateau planted with coconut, corn and tobacco, and a progressive town of 16,000 people. He took note of the imposing structures of the town like the church and convent, stone stairway or Inang-angan, and wharf; children going to school; an affluent community with well-kept environs; and a spring flowing from a cave on the northern edge of the town, after which the name Loon was coined.
1903 - the first official count of inhabitants was conducted nationwide. Loon’s population was described as fairly large at 18,114 residents. At that time, no other Bohol municipality, including Tagbilaran, registered more than 10,000 residents.
1914 - completion of the construction of the Gabaldon Building, the main structure of Catagbacan Elementary School, now Loon North Central Elementary School.
1915 - completion of the Gabaldon Building of the Loon (now Loon South) Central Elementary School.
1929 - completion of the American-style public plaza that features a monument dedicated to the national hero, the only Rizal monument topped by a replica of the Statue of Liberty; and a fountain that depicts the legend of Tubig-Loon.
June 1942 - arrival of Captain Francisco Salazar in Bohol (Catagbacan) from Mindanao via Leyte.
September 27, 1942 - Battle of Moalong, now jointly commemorated annually, since 2001, with the Municipal Day of Prayer for World Peace.
1946 - opening of Loon Institute (Rafael Palma College Branch), the town's first secondary school.
1948 - founding of Sacred Heart Academy, first sectarian high school, by Msgr. Felix Zafra.
1952 - establishment of the Loon Municipal Library during the incumbency of Mayor Juan ‘Aning’ M. Relampagos.
January 28, 1958 - Fr. Gorgonio C. Pueblos started serving the Mary Help of Christians (Auxilium Christianorum) Parish as its first parish priest.
1968 - Typhoon Reming destroyed most houses and damaged agricultural crops and livestock. It also destroyed the old municipal building, then used as Loon Central Annex in Moto Norte.
December 13, 1975 - energization of Loon by the Bohol Electric Cooperative (Boheco I); prior to this electric power was already available from the local power plant established by the municipal government in about 1968.
March 28-29, 1977 - The Loon Youth Team grabbed the grand championship of the first-ever Provincial Kabataang Barangay Sportsfest basketball finals that was participated in by all 47 municipalities previously competing in inter-town elimination rounds.
1979 - Loon hosted the annual National Science and Technology Fair which was participated in by high school students who won in the science fair (investigative projects) and quiz competitions in their respective regions.
February 20, 1988 - Canonical erection of San Lorenzo Ruiz de Manila Parish. Its first parish priest, Fr. Bernardito T. Getigan officially reported on May 12, 1988.
June 8, 1988 - the Loon Waterworks System received the Gawad Galing Pook for 1997-98.
December 15, 1990 - establishment of the Holy Cross Parish with Fr. Gaudioso C. Zamora as first parish priest.
September 2000 - the SidlaKasilak or Festival of Lights was mounted for the first time, with sectoral representatives each bearing a decorated lantern that they floated on the pond below the fountain at the Loon Public Plaza. Sixty-seven teachers, each representing a barangay, also brought beautifully adorned and lighted baskets.
November 19, 2000 - establishment of the Our Lady of Peace and Good Voyage Parish in Barangay Cuasi. Fr. Blair Lope M. Sabaricos, a Loonanon, was the first chaplain.
June 22, 2002 - Opening of the Loon South High School in Barangay Cuasi, the seventh secondary school in the town.
2002 - The Province of Bohol was conferred a Gawad Galing Pook for its coastal resource management program that includes the institutionalization of the Coastal Law Enforcement Council (CLEC). At that time, the CLEC of the First District was chaired by Mayor Cesar Tomas "Yul" M. Lopez, MD. Loon's efforts in enhancing heritage, culture and the arts also contributed much to another Galing Pook award received by the Province in recognition of its cultural renaissance program as a means to strengthen local governance.
2003 - Mayor Yul Lopez was conferred the Local Government Leadership Award as Outstanding Municipal Mayor of the Philippines, so far the first and only town mayor awardee from Bohol. The award was conferred on him by the Department of the Interior and Local Government, University of the Philippines, Ateneo de Manila University, De La Salle University and other reputable institutions on the basis of his exemplary achievements and leadership in local governance.
August 30 - September 8, 2005 - PaghiuSadya 2005, first global homecoming of Loonanons.
December 18, 2005 - inauguration of the 11.8-million-peso modular steel bridge on Tajang Pass which was constructed under the President's Bridge Program of the Department of the Interior and Local Government and the Austrian government.
January 2007 - diarrhea outbreak in Loon, caused by Shigella flexneri, a water-borne bacterium. The epidemic claimed the lives of at least 11, mostly children.
June 2007 - dengue outbreak that left at least three children dead.
November 22, 2007 - the Commission on Audit conferred on the Local Government Unit the following four recognitions: first Municipality in the entire country to implement the electronic New Government Accounting System (e-NGAS), LGU with the shortest e-NGAS roll-out period; LGU with the most updated budget reports; and LGU with the most updated financial statements.
November 27, 2007 - a storm surge heavily damaged the causeway on Tajang Pass and Tulay, the fish port in Napo.
December 15-16, 2007 - The first Loon Creative Industry Festival was launched. According to Mr. Blair Panong, DTI - Bohol representative, Loon is the first LGU in the entire country to have sponsored an activity of such kind.
February 25-29, 2008 - In celebration of National Arts Month, the Local Government Unit mounted an exhibit on the works of Loonanon artists, particularly in the fields of painting, sculpture, literary arts, mat-weaving, film and television, photography, music, theater, and fashion.