Nueve De Febrero Elementary School (Formerly Highway Hills Elementary School, Unit I) is serving two barangays - Barangay Pleasant Hills and Barangay addition Hills. Yet this school was named after Highway Hills, the neighboring barangay. Before the year 1966, almost all the children in Barangay Pleasant Hills were enrolled in Highway Hills Elementary School (main) on Samat Street being nearest school. Seeing the hazard that these children were encountering specially during rainy season, some parents and barrio officials made a petition to the school administrators that an annex be constructed in Pleasant Hills. That petition was granted, so in 1966 an annex with two classrooms was constructed at Barangay Pleasant Hills.

     The enrollment in that annex increased rapidly because the children in the adjoining barangay, Barangay Addition Hills were also accommodated. With this increase in enrollment, the annex expanded from two classrooms into two buildings with twelve classrooms. The Mandaluyong Municipal rented the additional two buildings at Fabella Compound along 9 De Pebrero Street for that purpose.On July 7, 1969 Highway Hills Elementary School, Unit I became a separate unit from Highway Hills Elementary School (main) District II.

          On April 4, 1981 a fire gutted the rented building at Fabella Compound. With permission from then Mayor Ernesto S. Domingo, the use of vacant lot with an area of 3,883 square meter along 9 De Pebrero Street had been fenced to the new school site. This concrete fence had been donated by DUMEZ Phiippines, an Italian Construction Firm based in the Philippines.

         By October 1981, Nueve De Febrero Elementary School had been placed under the jurisdiction of Mandaluyong III in line with policy of the Division of City Schools of Quezon City to equalize the number of schools in the three districts in Mandaluyong.

          The construction of additional classrooms resulted in giving up the annex at Pleasant Hills and the rented six classroom at Fabella Annex at the close of the school year 1986 - 1987.

          At the start of the school year 1987 - 1988, the school was operating on a three shift program to accommodate the displaced pupils of that annex but this situation lasted for almost two years while waiting for the completion of the 2 storey six classroom Abalos type building projects of the national and local government through DPWH initiated by Mayor Benjamin S. Abalos. These building had been completed on June 20, 1988 and were inaugurated and blessed on September 21, 1988.

          To augment the limited number of classrooms, Mrs. Paraluman G. Vicencio who assumed into office as principal of the school on April 18, 1988 continued to make requisition for another buildings. Through the coordinated effort of Mayor Benjamin S. Abalos and Senator Neptali A. Gonzales, a 3 storey 10 classroom building has been constructed replacing the old temporary 5 classroom building. The building was completed on January 15, 1993. On the same year, Mrs. Vicencio made it possible through the converted effort of Mayor Benjamin S. Abalos and Senator Alberto Romulo to build a 3 storey, 9 classroom building to replace the 3 classroom USAID building. It was completed on May 31, 1993. 

          The construction of a five-classroom building was initiated by then Mayor Ernesto S. Domingo. Through the concerted efforts of the then School Principal the late Mr. Agustin V. Garcera and the GPTCA President the late Mr. Dominador V. Fonseca, the construction of two classroom building which was inaugurated in March 1984 was donated by Mr. Han Sui Cheng, President and General Manager of Apollo Street Mill through the joint efforts of the Federation of Filipino-Chinese Chamber of Commerce

          In the same year 1984, a three-classroom building had been constructed as a joint undertaking on national government and the government of the United States of America was named USAID building.

          The construction of additional classrooms resulted in giving up the annex at Barangay Pleasant Hills and the rented six classrooms at Fabella Annex at the close of the school year 1986-1987.

          At the start of the school year 1987-1988, the school was operating on a three shift program to accommodate the displaced pupils of the annex, but this situation lasted for almost two years while waiting for the completion of the two storey six classroom Abalos type building and the Industrial Arts building funded by the infrastructure program for school building projects of the national and local named USAID building.

        Prior to her promotion as Division Supervisor, Mrs Paraluman G. Vicencio initiated to have another building to replace the old Filipino-Chinese building and the unfinished Multi-purpose H.E.building. It was fully completed under the administration of Ms. Erdelinda G. Diaz.

      Even if the number of classrooms have increased, still it can no longer accommodate its increasing population. To solve the existing problem, the Principal Ms. Erdelinda G. Diaz again made another request to replace the Industrial Arts buildingto a three storey nine classroom building.

         Through the joint effort of Dr.Pedro A. Ramos and the City School Board, the aforementioned building soon materialized. The new Abalos building housed the Principals' Office, clinic, and guidance room and the Grade VI pupils having a whole day session.

       Instead, the City Government through Mayor Neptali "Boyet" Gonzales purchased a vacant lot fronting the school. Not long enough under Mrs. Emma G. Arrubio (February 2005 - May 2006) the dedication, unveiling and groundbreaking ceremony of the 4 storey 16 classroom building was soon held.

          To accommodate the increasing population, a 28-classroom building was constructed and was fully completed under the administration of Mrs. Wilhemina O. Bautista (June 2006 - June 2008).

          The Building was inaugurated and blessed on June 28, 2007 but was named an independent school in SY 2009 - 2010 known as Pleasant Hills Elementary School (PHES).