Vancouver, British Columbia--(Newsfile Corp. - April 1, 2026) -  Riverside Resources Inc.  (TSXV: RRI) (OTCQB: RVSDF) (FSE: 5YY0) ("Riverside" or the "Company"), is pleased to announce the commencement of the Phase 2 exploration program at La Union Project in Sonora, Mexico. The program builds on the success of the 12-hole Phase 1 drill program announced January 22, 2026, which delivered a new sediment-hosted gold discovery at Luis Hill returning 42m grading 0.3 g/t gold. Funded by Questcorp, Phase 2 has mobilized teams to the field across four main target areas, where work will include geological mapping, geochemistry, geophysics, and a property-wide structural analysis.

"We are pleased to have a fully funded exploration program and have immediately activated our team in the field," said John-Mark Staude, President and CEO, Riverside Resources Inc. "I have just returned from Sonora, where the Phase 2 program is progressing well, with the Riverside team conducting safe, high-quality work encompassing sampling, mapping, geological targeting, and geochemistry with the aeromagnetic geophysics expansion launching shortly. Building directly on our Phase 1 results, including the high-grade channel sampling at Union Mine and the new sediment-hosted gold discovery at Luis Hill, we have multiple well-defined targets to advance. Riverside is pleased to continue working with partner Questcorp, and as a shareholder in Questcorp, our interests in the success of the Union Project are well aligned."

Planned exploration for this program includes:

• Follow-up work on sediment-hosted gold ("SHGD") targets identified during Phase 1 drilling, where gold was intersected in sedimentary rocks below the primary Carbonate Replacement Deposit ("CRD") host units, consistent with districts known to host both CRD and SHGD deposit styles.

• Underground follow-up sampling at the Union Mine, where the previously announced chip-channel interval on January 22, 2026, remains open on both ends and warrants further investigation.

• CRD targeting at the Famosa North area, where lead and zinc anomalies have never been drill-tested; field studies in this area will support upcoming drill targeting. The Famosa mineral concessions were recently consolidated into Riverside's land package, as announced on March 18, 2026.

• Structural geology work in the northern portion of the property, where consulting structural experts are working alongside Riverside's local field staff to refine drill targeting.

• Follow up on sediment-hosted gold targets in the eastern portion of the Union Project district.

• Follow-up exploration at Luis Hill, where Phase 1 drill hole UND25-9 returned 42m grading 0.3 g/t gold in sediment-hosted rocks representing a new style of Carlin-like gold mineralization for this part of Sonora. Phase 2 field work will expand upon this discovery to define additional drill targets.

Running concurrently with the field work described above is an expanded aeromagnetic drone survey that builds upon the Phase 1 geophysical dataset. The expanded survey will extend coverage in all directions of the mineral property, generating data that will support Phase 2 drill targeting in advance of a drilling program planned for early summer 2026.

Figure 1: Location of some of the targets at the Union project to be evaluated during the Phase 2 exploration program and locations of the initial Phase 1 drill holes which now can be further expanded during the Phase 2 program as well.

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As announced on March 18, 2026, the Famosa area mineral concessions have been formally transferred and consolidated into Riverside's land package. This strengthens the foundation for the Phase 2 work program, as the geology and mineralization trends within the Famosa area extend northward and eastward into the primary Phase 2 exploration focus zones.

The Union Project hosts multiple district-scale target areas, and the Phase 2 program is designed to systematically advance the most promising of these toward drill testing. The program will evaluate three distinct styles of mineralization identified during Phase 1: carbonate replacement deposit (CRD) mineralization, sediment-hosted gold in calcareous siltstones and carbonaceous sediments comparable to Nevada's Carlin-style deposits, and structurally controlled gold mineralization within quartzite units. With permits in hand, site access secured, and both a drill contractor and geophysical service provider selected, all logistics are advancing toward a summer 2026 drilling program.

About the Union Project

The Union Project is a district-scale carbonate replacement deposit (CRD) exploration project located in Sonora, Mexico. The project hosts historical mining areas and multiple exploration targets associated with gold, silver, zinc, and lead mineralization within carbonate and structurally controlled settings. Riverside operates the project through its Mexican subsidiary while advancing exploration in partnership with Questcorp.

Qualified Person

The technical content of the news release has been reviewed and approved by Freeman Smith, P.Geo. (British Columbia), a qualified person under National Instrument 43-101 who is non-independent and the Vice President Exploration for the Company.

About Riverside Resources Inc.:

Riverside is a well-funded exploration company driven by value generation and discovery. The Company has a strong balance sheet with over C$5,000,000 cash, no debt and tight share structure with a strong portfolio of gold-silver, copper, and REE assets and royalties in North America. Further information about Riverside is available on the Company's website at www.rivres.com.

ON BEHALF OF RIVERSIDE RESOURCES INC.

"John-Mark Staude"

Dr. John-Mark Staude, President & CEO

For additional information contact:

Certain statements in this press release may be considered forward-looking information. These statements can be identified by the use of forward-looking terminology (e.g., "expect"," estimates", "intends", "anticipates", "believes", "plans"). Such information involves known and unknown risks -- including the availability of funds, the results of financing and exploration activities, the interpretation of exploration results and other geological data, or unanticipated costs and expenses and other risks identified by Riverside in its public securities filings that may cause actual events to differ materially from current expectations. Readers are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this press release.

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