Question: State Road 78 historically extended to the northern tip of of a lake that covers how many sqmi?

Context paragraphs:
Lake Okeechobee: Lake Okeechobee ( ), also known as Florida's Inland Sea, is the largest freshwater lake in the state of Florida.  It is the eighth largest natural freshwater lake in the United States and the second largest natural freshwater lake (the largest being Lake Michigan) contained entirely within the contiguous 48 states.  Okeechobee covers 730 sqmi , approximately half the size of the state of Rhode Island, and is exceptionally shallow for a lake of its size, with an average depth of only 9 ft .  The lake is divided between Glades, Okeechobee, Martin, Palm Beach, and Hendry counties.  All five counties meet at one point near the center of the lake.

Citrus Center, Florida: Citrus Center is an unincorporated community in Glades County, Florida, United States, located on State Road 78 approximately 4 mi west of the junction of SR 78 and U.S. Route 27, west of Moore Haven.

Geography and ecology of the Everglades: The geography and ecology of the Everglades involve the complex elements affecting the natural environment throughout the southern region of the U.S. state of Florida.  Before drainage, the Everglades were an interwoven mesh of marshes and prairies covering 4000 sqmi .  The Everglades is simultaneously a vast watershed that has historically extended from Lake Okeechobee 100 mi south to Florida Bay (around one-third of the southern Florida peninsula), and many interconnected ecosystems within a geographic boundary.  It is such a unique meeting of water, land, and climate that the use of either singular or plural to refer to the Everglades is appropriate.  When Marjory Stoneman Douglas wrote her definitive description of the region in 1947, she used the metaphor "River of Grass" to explain the blending of water and plant life.

Florida State Road 990: State Road 990 (SR 990) is the 2.97 mi central section of the approximately 11.6 mi Killian Drive, also known as Killian Parkway, Southwest 104th Street and Southwest 112th Street and historically South Kendall Drive, located in southern Miami-Dade County, Florida.  Running from east to west, it serves to connect the community of The Hammocks with the village of Pinecrest via the community of Kendall, with State Road 990 connecting Southwest 107th Avenue (State Road 985) and the Don Shula Expressway (State Road 874) to the South Dixie Highway (U.S. Route 1).  Recognising the role the road played in southern Miami-Dade County's history and development, the section of State Road 990 between the Expressway and US 1 was designated the Killian Drive State Historic Highway by the Florida Senate in 1995.

Florida State Road 526: State Road 526 (SR 526) is a 12 mi east–west route in the Orlando MSA, located entirely in Orange County.  It runs from State Road 50 in Ocoee, to State Road 15, the frontage roads of State Road 408, in Orlando.  After the western terminus of SR 526, State Road 50, it becomes SR 439.  Between US 17 and the western terminus, it is known as County Road 526, and locally known as Old Winter Garden Road.  It crosses State Road 408 twice.  At the overpass of Interstate 4, State Road 526 runs north–south for 1 block.  It then heads into Downtown Orlando via Robinson Street and follows the northern shore of Lake Eola.  SR 526 next intersects State Road 15.  At the Orlando Executive Airport, it heads north–south and then ends at State Road 15, the frontage roads of State Road 408.

Lake Okeechobee Scenic Trail: The Lake Okeechobee Scenic Trail (LOST) is a 109 mile multi-use path around Lake Okeechobee, the seventh largest lake in the United States and the largest in the state of Florida.  The trail began as the Okeechobee Segment of the Florida National Scenic Trail (FNST), a 1,000 mile trail that runs from Miami to Pensacola.  The USDA and National Forest Service dedicated the Okeechobee Segment as part of the FNST in 1993.  Most of the trail is atop the 35-feet tall Herbert Hoover Dike.  The trail crosses five counties, Hendry, Glades, Okeechobee, Martin and Palm Beach.  Many stretches run along state and county highways, including Florida State Road 78.

Florida State Road 78: State Road 78 (SR 78) is the Florida Department of Transportation designation of the highway that historically extended from Pine Island Center on the Gulf Coast of Florida to the northern tip of Lake Okeechobee.  In the 1980s, two segments of the route were removed from state maintenance to county maintenance (and the road designations were changed to reflect the action).  More recently, SR 78 signs were removed from the four-mile-long stretch of US 27/SR 25 that was once a concurrency.  All three sections are signed east–west, even though the easternmost section is actually a north–south route.

Lakeport, Florida: Lakeport is an unincorporated community in Glades County, Florida, United States, located near the western shore of Lake Okeechobee, off State Road 78.  It is just south of the Brighton Seminole Indian Reservation.

Mule Creek, New Mexico: Mule Creek is an unincorporated community in Grant County, New Mexico, United States.  Mule Creek is located on New Mexico State Road 78 46 mi northwest of Silver City.  Mule Creek has a post office with ZIP code 88051.

State Route 78 (Arizona–New Mexico): Arizona State Route 78 and New Mexico State Road 78 (SR 78) are a pair of adjoining state highways located in eastern Arizona and western New Mexico linking U.S. Route 191 (US 191) and Arizona State Route 75 near Greenlee County Airport to US 180 northwest of Cliff, New Mexico.  It is also known in its Arizona stretch as Mule Creek Road.

Supporting paragraphs: Florida State Road 78 Lake Okeechobee
Answer: 730